Copy Number Alterations in HNSCC with or without Oncogene Expressing Human Papillomavirus . Homo sapiens

Oncogene expressing human papillomavirus type 16 (HPV16) is found in a subset of head and neck squamous cell carcinomas (HNSCC). HPV16 drives carcinogenesis by inactivating p53 and pRb with the viral oncoproteins E6 and E7, reflected by a low level of mutations in TP53 and allelic loss at 3p, 9p and 17p, genetic changes frequently found in HNSCCs of non-viral etiology. We hypothesize that two pathways to HNSCC exist: one determined by HPV16 and one by environmental carcinogens. To define the critical genetic events in these two pathways, we now present a detailed genome analysis of HNSCC with and without HPV16 involvement by employing high resolution micro-array comparative genomic hybridization. Four regions showed alterations in HPV-negative tumors that were absent in HPV-positive tumors: losses at 3p11.2-26.3, 5q11.2-35.2, 9p21.1-24, and gains/amplifications at 11q12.1-13.4. Also, HPV16-negative tumors demonstrated loss at 18q12.1-23, in contrast to gain in HPV16-positive tumors. Seven regions were altered at high frequency (>33%) in both groups: gains at 3q22.2-qter, 5p15.2-pter, 8p11.2-qter, 9q22-34.1, 20p-20q and losses at 11q14.1-qter and 13q11-33. These data show that HNSCC arising by environmental carcinogens are characterized by genetic alterations that differ from those observed in HPV16-induced HNSCC, and most likely occur early in carcinogenesis. A number of genetic changes are shared in both tumor groups and can be considered crucial in the later stages of HNSCC progression. Overall design: Tumor DNA is isolated from fresh frozen tissue. Tumor DNA is enriched by microdissection. Reference DNA is isolated from blood of normal individuals of the opposit gender.