snoRNAs play a central role in post-transcriptional modifications, primarily guiding 2'-O-ribose methylation and pseudouridylation of ribosomal RNAs (rRNAs) and small nuclear RNAs (snRNAs). These modifications enhance molecular interactions, promote rRNA folding, and ultimately optimize ribosome and spliceosome function (16,17). snoRNAs function as guide RNAs within snoRNP complexes, which include core proteins that provide catalytic activity and ensure target specificity via complementary base pairing (18-20).

snoRNAs are classified into 2 main groups: C/D box snoRNAs (SNORDs) and H/ACA box snoRNAs (SNORAs), which direct methylation and pseudouridylation, respectively. In addition to these, a third category, small Cajal body-specific RNAs (scaRNAs), exhibits hybrid features of both SNORDs and SNORAs, combining their functional properties to perform specialized roles in RNA modification. This diversity in snoRNA classes underscores their versatility and importance in RNA processing and cellular function (21). Characterization, biogenesis and canonical function of snoRNAs are shown in Fig. 1.

SNORDs are characterized by conserved C (RUGAUGA) and D (CUGA) motifs near their termini, forming a kink-turn structure. They also contain internal C' and D' boxes. These structural elements scaffold proteins such as nucleolar protein (NOP)56, NOP58, 15.5 kilodalton protein, and fibrillarin, which are essential for the stability, localization, and functional integrity of snoRNPs.

The target specificity of SNORDs is mediated by a short guide region, typically 10-21 nucleotides in length, located upstream of the D or D' boxes. This region, referred to as the antisense element, plays a critical role in recognizing and binding to complementary sequences on target RNAs. Fibrillarin, a core component of the snoRNP complex, serves as the catalytic force for methylating the fifth nucleotide upstream of the D or D' box motif, thus fulfilling the essential modification role of snoRNP. This precise targeting mechanism ensures the accurate and site-specific 2'-O-methylation of rRNAs and snRNAs, highlighting the sophisticated regulatory role of SNORDs in RNA processing and modification (22-24).

SNORAs are characterized by a 3' ACA tail and 2 hairpin structures connected by a hinge region containing a conserved (ANANNA) motif, known as the H motif or BOX H. Each hairpin contains an internal loop, termed the pseudouridylation pocket, which base-pairs with target RNAs. Typically, the uridine residue in the target RNA, positioned 14-15 nucleotides upstream of the H or ACA box, undergoes pseudouridylation. This reaction is catalyzed by dyskerin, a pseudouridine synthase within the H/ACA-associated snRNP complex, which also includes nuclear H/ACA ribonucleoprotein 2 (NHP2), NOP10, and glycine-argine rich protein 1 (25-27).

scaRNAs are distinguished by their localization within Cajal bodies, specialized sub-nuclear compartments, mediated by a unique UGAG motif. These RNAs play critical roles in spliceosome and ribosome biogenesis, facilitating the precise methylation and pseudouridylation of snRNAs and rRNAs. By guiding these modifications, scaRNAs ensure the structural and functional integrity of these essential molecular complexes, underscoring their importance in cellular processes (28,29).

snoRNAs constitute a diverse and functionally versatile class of RNA molecules with multifaceted roles in cellular processes. Notably, approximately half of human snoRNAs are 'orphans' with uncharacterized functions (30). Recent studies have revealed diverse noncanonical roles beyond rRNA/snRNA modification, expanding our understanding of their roles beyond traditional paradigms and revealing previously unexplored biological activities (31,32).

Emerging research indicates that snoRNAs may possess an expanded functional repertoire beyond prior recognition, encompassing diverse modification types and a broader spectrum of RNA targets. For instance, the orphan snoRNAs snR4 and snR45 facilitate the acetylation of two N4 cytidine residues in 18S rRNA by guiding the cytidine acetyltransferase Kre33 to its target sites, a process critical for maintaining the accuracy of protein synthesis (33). Advanced techniques such as chimeric enhanced crosslinking and immunoprecipitation have uncovered novel snoRNA-rRNA/snRNA interactions in an RNA-binding protein-dependent manner, revealing novel interactions and regulatory roles in RNA biogenesis (34).

Post-transcriptional modifications of tRNAs, especially at the anticodon wobble position and the 3' end, play a vital role in stabilizing mRNA-tRNA interactions. For example, the methylation of cytidine at the wobble position, guided by SNORD97, targets the anticodon loop of elongator tRNAMet through sequence complementarity, enhancing tRNA functionality and protecting it from cleavage by stress-induced endonucleases such as angiogenin (35). Although recent studies have illuminated specific snoRNA-tRNA interactions (36,37), earlier co-immunoprecipitation experiments had already revealed physical associations between snoRNAs and tRNAs (38,39). This suggests that numerous additional interactions remain to be discovered, highlighting the profound complexity of snoRNA-mediated regulatory networks.

Beyond their well-documented roles in ncRNA modification, high-throughput sequencing of ligated RNAs has uncovered surprising interactions between snoRNAs and mRNAs. A prominent example is SNORD83B, an orphan snoRNA that bolsters the stability of mRNAs-including NOP14, ribosomal protein S5, and serine/arginine-rich splicing factor 3 via direct base-pairing interactions (40). Research reveals that SNORA73 forms stable secondary structures with target mRNAs via non-canonical RNA binding sequences. Additionally, SNORA73 engages with 7SL RNA, a crucial element of the signal recognition particle (SRP), assembling a 'mRNA-snoRNA-7SL RNA' ternary complex. This complex significantly boosts the binding affinity of target mRNAs to the SRP, facilitating the efficient translocation of the translational complex to the endoplasmic reticulum. Thereby, this interaction promotes the effective translocation and release of secretory proteins, revealing a novel role for snoRNAs in orchestrating protein trafficking and secretion (41). These findings highlight the wide-ranging and multifaceted roles of snoRNAs in cellular processes, extending well beyond their canonical functions in RNA modification.

Research has revealed that SNORD80, an intron-encoded SNORD originating from the GAS5 gene, orchestrates the 2'-O-methylation of GAS5 lncRNA. This critical modification bolsters the stability of the lncRNA, triggering its subsequent upregulation and ultimately fine-tuning cellular stress response mechanisms (42).

Some snoRNAs function by binding proteins. SNORA13 departs from canonical snoRNA function by regulating cellular senescence independently of ribosomal interactions. Rather than modulating ribosomal translation, it directly binds MDM2, thereby activating the p53 pathway and inducing senescence (30). By contrast, SNORD46 governs metabolism and immune function through its specific interaction with interleukin (IL)-15. While wild-type SNORD46 binds IL-15 via G11, the G11A mutation significantly enhances this binding affinity and promotes obesity in knockin mice. Mechanistically, SNORD46 inhibits IL-15-dependent phosphorylation of CD36 and monoglyceride lipase in adipocytes-mediated by feline sarcoma-related kinase, effectively suppressing lipolysis and thermogenic browning. Concurrently, in natural killer (NK) cells, SNORD46 disrupts IL-15-driven autophagy, reducing NK cell viability during obesity. Notably, SNORD46 inhibitors effectively counteract these effects, alleviating obesity and restoring critical NK cell functions, including the antitumor efficacy of chimeric antigen receptor-NK therapy (43). Similarly, the snoRNA snR107 plays a distinct regulatory role in meiosis by interacting with the RNA-binding proteins meiosis mitotic inhibitor 1 and meiosis 2. This interaction establishes a reciprocal inhibition mechanism that tightly controls meiotic gene expression throughout sexual differentiation (44). SNORA73 exhibits a unique mechanism involving 5' end non-canonical structural binding to poly(ADP-ribose) polymerase 1 (PARP1), inhibition of PARP1 auto-PARylation, and formation of a specialized snoRNP complex with dyskerin pseudouridine synthase 1/NHP2 to modulate cancer genome stability (45).

snoRNAs have surfaced as pivotal regulators of alternative splicing, critically influencing the processing of key mRNAs such as 5-hydroxytryptamine serotonin receptor 2c (HTR2C). This intricate regulation is orchestrated by the orphan snoRNA SNORD115, which harbors an 18-nucleotide sequence perfectly complementary to the alternative exon 5b within HTR2C mRNA. SNORD115 actively promotes the inclusion of exon 5b, yielding a long, functional receptor isoform; conversely, its exclusion produces a non-functional variant. Beyond its splicing role, SNORD115 directly competes with adenosine deaminases acting on RNA (ADAR) enzymes, which catalyze crucial adenosine-to-inosine editing within this same region. Such editing can markedly alter three amino acids in exon 5, profoundly impacting G-protein coupling and downstream signaling cascades of the receptor. The influence of SNORD115 extends to at least five additional alternative splicing targets, powerfully underscoring its notable regulatory versatility (46). Similarly, SNORD116, residing at the same chromosomal locus as SNORD115, is implicated in splicing regulation, with numerous predicted binding sites precisely mapping to exon junctions (47). Other snoRNAs, such as SNORD27, demonstrably direct the splicing of the E2F7 transcription factor (4), while SNORD88C regulates the alternative splicing of fibroblast growth factor receptor 3 (FGFR3) by effectively masking cryptic splice sites, thereby preventing aberrant exon inclusion (48). These compelling findings illuminate the rapidly expanding role of snoRNAs in meticulously fine-tuning mRNA splicing and their profound potential impact on gene expression and cellular function.

Beyond their well-established roles in post-transcriptional modifications and alternative splicing regulation, snoRNAs are gaining growing recognition for their involvement in mRNA 3'-end processing. Previous research reveals that a specific subset of snoRNAs interacts directly with the mammalian 3'-end processing complex, illuminating their function in poly(A) site selection. These snoRNAs specifically associate with factor interacting with poly(A) polymerase 1 (Fip1), a key cleavage and polyadenylation specificity factor component. Among them, SNORD50A has emerged as a pivotal regulator, inhibiting 3' mRNA processing for specific transcripts by occupying the interaction site between Fip1 and the poly(A) signal (3).

While snoRNAs are traditionally linked to nucleolar functions, accumulating evidence indicates they also exert biological roles beyond the nuclear compartment. Under cellular stress conditions, specific snoRNAs, including SNORD32A, SNORD33, and SNORD35A, have been observed to accumulate in the cytosol, suggesting potential extranuclear functional activities (49).

The precise mechanisms generating smaller fragments from longer snoRNAs remain elusive. Current research confirms that certain snoRNA-derived miRNAs, including those from H/ACA scaRNA15 (ACA45), require the ribonuclease III Dicer (DICER) enzyme for their biogenesis. Comparative deep sequencing analysis of wildtype vs. DICER/DiGeorge syndrome critical region 8 (DGCR8) knockout embryonic stem cells revealed profound alterations in the length distribution patterns of SNORA-sdRNAs. These findings compellingly suggest the microprocessor complex (DICER/DGCR8) plays a substantial role in a process analogous to miRNA biogenesis. Conversely, the production of smaller fragments from SNORD appears to operate through a distinct mechanism, evidenced by their continued generation despite the absence of functional DICER/DGCR8 components. However, comprehensive cross-linking studies of cellular RNAs with DGCR8 demonstrate extensive interactions between snoRNAs and DGCR8. Crucially, DGCR8-mediated cleavage of snoRNAs occurs independently of DICER, indicating the potential existence of an alternative sdRNA biogenesis pathway. This alternative route may involve other enzymatic components associated with DGCR8 (50,51). Based on their biogenesis and structural features, sdRNAs can be broadly classified into three categories: i) H/ACA-derived sdRNAs, typically 20-24 nt fragments originating from the 3' terminus; ii) C/D-derived sdRNAs, which include both longer (>26 nt) and shorter (17-19 nt) fragments primarily derived from the 5' end; and iii) sno-derived P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs), which are associated with PIWI proteins and range from 26-31 nt (52,53). These distinct classes exhibit diverse functional properties, as discussed below.

High-throughput sequencing studies have revealed that snoRNAs undergo specific cleavage to produce smaller functional fragments, rather than simply suffering random degradation. This conclusion is bolstered by several key observations: First, the expression patterns of sdRNAs exhibit striking conservation across diverse species; second, an inverse relationship often exists between snoRNA abundance and sdRNA production, suggesting that highly abundant sdRNAs may originate from relatively low-expressed snoRNAs; and third, the selective presence of stable fragments from specific snoRNAs regions, as opposed to random degradation products from other parts of the same molecule, strongly implies the existence of a regulated stabilization mechanism (48).

From a structural and functional perspective, sdRNAs can be classified into distinct categories based on their biogenesis and physical characteristics. SNORAs primarily generate 20-24 nucleotide fragments preferentially derived from their 3' termini. By contrast, SNORDs produce two distinct size classes: Longer fragments over 26 nucleotides and shorter fragments ranging from 17-19 nucleotides, with the latter primarily originating from the 5' end. This phenomenon of sdRNA production appears pervasive, with experimental evidence demonstrating that >50% of all snoRNAs are capable of generating these smaller fragments (54,55). While the biological functions of numerous sdRNAs remain incompletely characterized, their widespread occurrence and evolutionary conservation strongly suggest diverse regulatory roles, some of which are increasingly being revealed through ongoing research. The biogenesis and function of sdRNAs are shown in Fig. 2.

A particularly intriguing potential function of sdRNAs lies in their capacity to serve as a novel source of miRNA-like molecules. This hypothesis was initially investigated through comprehensive analysis of small RNAs co-immunoprecipitated with Agonaute RNA-induced silencing complex (RISC) catalytic component (AGO)1 and AGO2 proteins in 293 cells. Notably, among the AGO2-associated fragments, researchers identified a functionally significant sdRNA derived from ACA45. Extensive functional characterization, combining luciferase reporter assays with sophisticated bioinformatic prediction tools, revealed that ACA45 exhibits canonical miRNA-like activity by specifically targeting CDC2L6 mRNA. While ACA45 shares the requirement for DICER in its maturation pathway with classical miRNAs, it displays a distinctive processing mechanism that bypasses Drosha involvement (7). Evidence suggests that small RNAs processed from snoRNAs can adopt microRNA (miRNA)-like functions, though most associate with Argonaute proteins at levels insufficient to elicit detectable silencing activity (56). Supporting this notion, Brameier et al identified 11 distinct snoRNA-derived sequences capable of integrating into the RISC and mediating effective gene silencing. These 'sno-miRNAs' originate from SNORDs, including snR39b, U3 (two loci), U78, HBII-336, HBII-429, HBII-142, U27, U83a, U74, and U15a, and exhibit miRNA-like repression of reporter-gene mRNAs (57).

Emerging evidence has established snoRNAs as a significant source of piRNAs, a distinct class of 26-31 nucleotide ncRNAs that form functional complexes with PIWI proteins, a specialized subgroup within the Argonaute protein family. These snoRNA-derived piRNAs participate in crucial biological processes, including transposon silencing and epigenetic regulation of gene expression. In a pivotal study conducted in primary T lymphocytes, researchers identified multiple piRNA candidates originating from snoRNAs. Particularly noteworthy was the discovery of a piRNA derived from SNORD63, which specifically interacts with an intronic sequence of the IL-4 pre-mRNA. This interaction facilitates the recruitment of the Trf4-Air2-Mtr4 complex, subsequently leading to the targeted degradation of IL-4 mRNA by nuclear exosomes (58).

Further expanding our understanding of snoRNA-derived piRNA functions, another investigation revealed that a piRNA originating from SNORD75 exhibits dual binding capability to PIWI-like protein 1 (PIWIL1) and PIWI-like protein 4 (PIWIL4) proteins. This interaction triggers a significant epigenetic transition, characterized by the replacement of repressive histone marks (H3K27me3) with active marks (H3K4me3) at specific genomic loci. This epigenetic reprogramming leads to transcriptional activation of the TNF-related apoptosis-inducing ligand (TRAIL) tumor suppressor gene, demonstrating the potential of snoRNA-derived piRNAs in regulating critical cellular processes and maintaining genomic stability (59).

Notably, a subset of sdRNAs exhibit near-perfect complementarity to target mRNAs, enabling them to direct transcript cleavage in a manner analogous to siRNAs.

Building on this concept, snoRNA modulator of gene expression vectors have been developed as a versatile tool for protein replacement in cultured cells. These vectors enable the efficient substitution of endogenous cellular proteins with tagged or mutated recombinant variants, offering a powerful approach for functional studies (60).

SNORD115 has emerged as a key regulator in the alternative splicing of HTR2C pre-mRNA, specifically facilitating the inclusion of exon 5b to generate an extended variant. This regulatory function is particularly noteworthy as it occurs independently of the extensive RNA modifications typically required for the synthesis of long mRNA isoforms (61). The splicing regulatory capacity of SNORD115 extends beyond HTR2C, as it has been demonstrated to influence alternative splicing events in other pre-mRNA targets (62) Similarly, SNORD88C has been identified as a modulator of FGFR3 splicing events. Both SNORD115 and SNORD88C undergo specific processing to yield smaller fragments, with several of these sdRNAs overlapping with regions implicated in splicing regulation. However, the precise contribution of these sdRNA fragments, as opposed to the full-length snoRNAs, in splicing modulation remains to be fully elucidated (48). The mechanistic basis of sdRNA-mediated splicing regulation is not yet completely understood, but emerging evidence suggests a potentially significant role for interactions with a distinct group of heterogeneous (hn) RNPs. These hnRNP interaction partners differ from those associated with full-length snoRNAs and are themselves known to participate in splicing regulation.

Fundamental in vitro and in vivo models have elucidated the capacity of sdRNAs to actively drive or suppress tumor progression through complex molecular networks. In androgen-resistant prostate cancer (AR-PCa), specific fragments (sdRNA-D19b and sdRNA-A24) were shown to promote tumor aggressiveness by suppressing the expression of tumor suppressor genes CD44 and CDK12, thereby enhancing cellular proliferation, metastatic potential, and chemoresistance (161). Similarly, Patterson et al (162) revealed that SNORD93 undergoes processing into a functionally active, miRNA-like fragment (sdRNA93). This specific sdRNA was shown to regulate sarcosine metabolism by modulating pipecolic acid and sarcosine oxidase expression, directly driving cancer cell invasiveness (162). Conversely, certain sdRNAs exert potent tumor-suppressive effects. In breast cancer models, a specific sno-derived piRNA from the GAS5 locus (pi-sno75) actively upregulated the TRAIL pathway to induce apoptosis (59).

Clinically, the profound dysregulation of these molecules is consistently reflected in patient tissue cohorts. In pancreatic ductal adenocarcinoma (PDAC), comprehensive RNA sequencing has identified severe sdRNA dysregulation, with specific fragments such as hsa-sno-HBII-85-29 showing pronounced downregulation and hsa-sno-HBII-296B exhibiting high upregulation in tumor tissues (163). More broadly, by integrating small RNA sequencing data from 10,262 patient samples across 32 cancer types, Chow et al (164) constructed a comprehensive pan-cancer sdRNAome landscape. This landmark analysis revealed that sdRNA expression signatures are highly cancer-specific and possess the potential to independently stratify patient survival outcomes (164).

Beyond tissue associations, sdRNAs are emerging as highly translatable clinical tools, particularly in the realm of tumor immunology. A substantial cohort of sdRNAs demonstrates notable correlations with critical features of the tumor-immune microenvironment, including the expression of immunosuppressive markers, levels of CD8⁺ T-cell infiltration, cytolytic T-cell activity, and tumor vascularization patterns (164). These specific immune-associated sdRNA signatures hold immense translational potential as predictive biomarkers for stratifying patient responses to immunotherapy (164). Furthermore, the identification of functionally active sdRNAs driving chemoresistance in advanced malignancies such as AR-PCa highlights the need for their further investigation as novel therapeutic targets (161).

To synthesize these findings, sdRNAs represent a previously underappreciated yet functionally prevalent class of ncRNAs. From orchestrating metabolic and epigenetic shifts to serving as candidate prognostic indicators and immune-microenvironment classifiers, sdRNAs demonstrate substantial clinical relevance. Transitioning these molecules from mechanistic discovery toward targeted clinical applications represents a critical and highly promising frontier in precision oncology.

Recent clinical investigations highlight the diagnostic potential of circulating snoRNAs, particularly when multiplexed with conventional markers. For instance, in NSCLC, integrating diminished serum exosomal SNORD116 and SNORA21 levels with conventional biomarkers (cytokeratin 19 fragment 21-1 and CEA) surged the diagnostic accuracy to an AUC of 0.917, effectively distinguishing metastatic from non-metastatic disease (167). Similarly, in ccRCC, a panel of four EV-associated snoRNAs (SNORD99, SNORD22, SNORD26, and SNORA50C) isolated from non-invasive urine samples has emerged as a candidate diagnostic tool (153). Furthermore, a discovery-stage clinical study in pancreatic cancer identified a multi-marker panel (WASP family member 2, ADP-ribosylation factor 6, SNORA74A, and SNORA25) that exhibited promising diagnostic value (AUC >0.9), surpassing the standard carbohydrate antigen 19-9 biomarker in accurately detecting early-stage (0-IIA) pancreatic cancer (168).

Despite their clinical promise, significant technical hurdles hinder the accurate identification and quantification of circulating snoRNAs. Key challenges include RNA isolation biases stemming from their small size (60-300 nt), the lack of polyadenylation tails that complicates standard library preparation, and highly stable secondary structures that impair reverse transcription efficiency. Furthermore, the rigorous clinical translation of circulating snoRNAs is heavily dependent on overcoming critical methodological bottlenecks. These include standardizing specimen types (such as serum vs. plasma vs. EVs), optimizing pre-analytical handling (such as centrifugation protocols and minimizing freeze-thaw cycles), establishing consensus strategies for data normalization (given the lack of universal endogenous controls in biofluids), and selecting appropriate detection platforms (reverse transcription-quantitative PCR vs. small RNA-sequencing) to ensure cross-study reproducibility. However, recent advances in small RNA-sequencing technologies, including specialized adapter designs for non-polyadenylated RNAs, improved reverse transcriptases for structured RNAs, and snoRNA-specific bioinformatic pipelines, have markedly enhanced analytical sensitivity (169,170). These methodological refinements are actively accelerating the exploration of circulating snoRNAs as candidate liquid biopsy biomarkers, although standardizing these protocols for definitive clinical application requires further extensive investigation.

While the precise molecular mechanisms of snoRNAs in tumorigenesis remain incompletely characterized, growing evidence suggests these ncRNAs are potential candidates for cancer therapy. The recent development of snoRNA-enriched kethoxal-assisted RNA-RNA sequencing (snoKARR-seq) technology represents a paradigm shift, enabling the transcriptome-wide mapping of snoRNA-mRNA interactions and identifying over 1,000 novel snoRNA-mRNA pairs. These discoveries challenge traditional paradigms by revealing modification-independent regulatory roles, thereby exponentially expanding the potential therapeutic target space for rational drug design (41). Furthermore, proof-of-concept research, such as the engineered expression of SNORA73 fused to a secreted green fluorescent protein reporter to modulate protein secretion pathways, suggest that artificial snoRNAs could potentially compensate for deficient secretory proteins in malignancies (41).

The past decade has witnessed notable progress in translating ncRNA targets into precision medicine (171). NATs, primarily antisense oligonucleotides (ASOs), ASO gapmers, and LNA oligonucleotides, have emerged as the most promising modalities for snoRNA-directed interventions. Preclinical success using ASOs is well-documented across multiple malignancies. For instance, ASO-mediated silencing significantly suppressed tumor growth and tumorigenesis in HCC (SNORD17, SNORD88B, SNORA74A) (87,91,172), PDAC (SNORA23) (173), OC (SNORA70E, SNORD9) (133,136), and EC (SNORD89, SNORD104, SNORD99) (141-143). Beyond monotherapy, NATs show profound synergistic potential and ASO-mediated inhibition of SNORA13 was revealed to synergize with 5-fluorouracil in CRC (174), while LNAs targeting SNORA38B significantly enhanced CD8⁺ T-cell infiltration, sensitizing NSCLC to ICB therapy (114).

Although intrathecal administration of ASOs has demonstrated clinical safety in human trials (175), broad oncological application faces significant barriers. To date, no ASO or LNA drugs have received FDA approval specifically for cancer treatment, primarily due to unresolved challenges regarding tumor-specific delivery and immune modulation. Emerging non-viral delivery strategies, such as engineered liposomes and hybrid carriers, show promise in addressing these limitations.

Consequently, SMDs represent a highly attractive parallel frontier. Compared with NATs, SMDs offer superior solubility, enhanced metabolic stability, lower production costs, and easier cellular penetration (176). Crucially, snoRNAs present multiple druggable structural features, including complex secondary/tertiary structures, conserved functional motifs, and distinct protein interaction interfaces within snoRNP complexes. While dedicated snoRNA-focused high-throughput screening campaigns are still in their infancy, the demonstrated success of miRNA-targeted screening platforms and in silico models provides a strong and viable precedent for the development of snoRNA-targeted SMDs (177).

Despite these promising preclinical results, the clinical translation of snoRNA-targeted therapeutics faces several hurdles that must be addressed: i) Efficient delivery to extrahepatic tumor tissues; ii) mitigating off-target effects and innate immune sensor activation; iii) overcoming the nuclear localization barrier of numerous snoRNAs; and iv) defining the stoichiometric requirements for functionally disrupting snoRNP complexes. Overcoming these barriers will require interdisciplinary innovations combining RNA chemistry, nanomedicine, and tumor biology.