A putative oncogenic role for MPP11 in head and neck squamous cell cancer

Genetic alterations of chromosome 7 are common in human cancer. Furthermore , previous studies have supported the presence of a gene important in a bro ad range of cancers at 7q22-31.1, There is evidence that supports an oncoge nic function for this putative gene, as well as evidence that supports a tu mor suppressive role. In this study, we used a cross-species candidate gene approach in combination with physical mapping to identify MPP11 as a candi date for the putative cancer-related activity at 7q22-31.1. We then analyze d primary head and neck squamous cell tumors (HNSCCs) for loss of heterozyg osity/allelic imbalance (LOH/AI) at the MPP11 genomic locus. Thirty-eight p ercent of tumors examined displayed LOH/AI involving the MPP11 genomic locu s. Mutation analysis of MPP11 in the latter samples did not identify any in activating mutations, However, immunohistochemical staining of primary tumo r sections and Western blot analysis of HNSCC cell lines revealed a tumor-s pecific high level of expression of MPP11p, Fluorescence in situ hybridizat ion analysis done on the cell lines identified increased chromosome 7 copy number with a concomitant increase in MPP11 copy number. These results sugg est an oncogenic role for MPP11 in HNSCC.