MOLECULAR ABNORMALITIES OF CHROMOSOME-19 IN MALIGNANT GLIOMAS - PREFERENTIAL INVOLVEMENT OF THE 19Q13.2-Q13.4 REGION

A deletion mapping analysis of chromosome 19 was performed on a series of 101 samples derived from malignant gliomas. A total of 35 tumors d isplayed different deletions for the loci studied (D19S21, D19S11, D19 S74, D19S7, D19S8, CKM, and D19S22). In most instances, losses involvi ng the long arm markers of chromosome 19 were observed, and only four samples were characterized by losses on the short arm. No tumor was fo und displaying loss of both short and long arm markers. The higher fre quency of deletions was detected in tumors with a major oligodendrogli al component: 76% of samples included in this group displayed losses a t 19q. Among the astrocytic tumors, the frequency of 19q alterations v aried as follows: 11% in pilocytic astrocytomas, 17% in astrocytomas g rade II, 10% in anaplastic astrocytomas and 21% in glioblastoma multif orme. No ependymoma was found displaying allele loss on chromosome 19. The common region of overlap for the 19q deletions observed involves primarily the distal portion of the long arm, 19q13.2-q13.4. In agreem ent with previous reports, these data suggest the non-random involveme nt of a tumor suppressor gene located at 19q13 in the genesis or progr ession of malignant gliomas.