Correlation of DNA copy number changes to malignancy in oral squamous cell carcinomas by comparative genomic hybridization

Abstract

To compare clinical and histopathological findings to tumor DNA copy number changes, comparative genomic hybridization (CGH) was performed on 18 primary oral squamous cell carcinomas. Copy number increases were most frequently observed on 8q, 3q, 13q, 11p, and 11q, while copy number decreases most frequently on 10q, 1p, 18q, 9p, and 19q. Copy number changes in relationship to WHO grading were examined with the result that DNA copy number increase on chromosome 6p23-25 was characteristically observed in the groups of Grade II and Grade III, and DNA copy number decreases on chromosomes 9p21 and 11p11-13 were observed in the same groups. Furthermore, comparison of DNA copy number changes to TNM classification indicated that the decreases on chromosomes 1p36 and 10q25-26 might be related to tumor progression. Moreover, the relationship of DNA amplification or deletion to metastasis was investigated. It was found that the majority of the metastasis-positive tumors showed increases on 3q26 and 17q12-21 and showed decreases on chromosome 18q21. The data suggested that these DNA copy number changes on each chromosome in the three categories might be associated with tumor cell differentiation, tumor size, and lymph node metastasis.