Loss of 3p26.3 is an independent prognostic factor in patients with oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common malignancy worldwide and the prognosis for patients with advanced-stage OSCC is particularly poor. To identify DNA copy number aberrations and candidate genes associated with a poor or favorable outcome, we analyzed the genome profiles of OSCC tumors by array-based comparative genomic hybrid­ization (A-CGH). This technique uses DNA microarray technology to detect genomic copy number variations at a higher resolution level than chromosome-based CGH. Fifty patients with primary OSCCs were included in the study. Of these 50 patients, 37 were treated surgically and 13 were treated without surgery and had received irradiation and/or chemotherapy. All samples were analyzed by A-CGH. Gains were detected frequently (>50%) at chromosomal regions 5p15.33, 7p22.3, 8q21.1-24.3, 9q34.3, 11q13, 16p13.3 and 20q13.3. Losses were frequently detected at 3p22, 3p14 and 4q35.2. High-level gains were recurrently (>10%) detected at each of 5p15, 7p22, 7p11, 8q24, 11q13, 11q22 and 22q11. Gains of 2p25.1, 11p15, 16p13.3, 16q24.3 and 20q13.3 were inversely correlated with nodal metastasis. In 37 of the 50 OSCC patients treated with surgery, gains of 8q12.1-24.22 and losses of 3p26.2-3 were associated with disease-specific survival (p<0.01). Loss of a 0.2 Mb chromosomal region in 3p26.3 was associated with a poor prognostic outcome in the Kaplan-Meier analysis (p<0.01 by the log-rank test). Multivariate analysis revealed that loss of 3p26.3 is an independent prognostic factor (p<0.01) of OSCC. Loss of a 0.2 Mb chromosomal region in 3p26.3 including the CHL1 (cell adhesion molecule with homology to L1CAM1) gene was identified as a novel potential marker for predicting the prognosis of patients with OSCC.