PTEN and Cancer

Genetic evidence strongly suggested that a tumor suppressor was located on chromosome 10. During the development of glioblastoma, one copy of chromosome 10 was typically lost (1 ). Cytogenetic and molecular analysis revealed partial or complete loss of chromosome 10 in bladder, endometrial, and prostate cancer (2 ,3 ). These studies implicated 10q23 as a chromosomal region likely to contain one or more important tumor suppressor genes. When wild-type chromosome 10 was reintroduced into glioblastoma cell lines, it reduced the ability of these cell lines to form tumors in nude mice, in part due to inhibition of angiogensis (4 ). During the same year (1996), a linkage analysis report of a cancer predisposition syndrome, Cowden disease (CD), determined that a CD locus was present on chromosome10q23 (5 ). These findings greatly bolstered the idea that chromosome 10q23 contained a novel tumor suppressor gene whose loss was key in the formation of several types of cancer.