Search

A combined cytogenetic and molecular analysis was performed on 11 cases of papillary thyroid carcinoma. A simple karyotypic abnormality was detected in five tumors, whereas six had no apparent chromosome change. In four of five rearranged cases the presence of a specific chromosomal abnormality involving chromosome 10 (cases 1 and 2) and chromosome 1 (cases 3 and 4) was associated with the rearrangement of two protooncogenes: RET and NTRKI (formerly trk), respectively, with different donor genes. Moreover, the chromosomal localization of the involved genes and the type of chromosomal change observed suggested that RET and NTRKI activation occurred by intrachromosomal rearrangements. The six cases with normal karyotype did not show RET or NTRKI activation. These findings suggest that a combined cytogenetic and molecular approach would be useful in understanding the pathogenesis of thyroid neoplasia.

A cytogenetic analysis of a lung metastasis of an adamantinoma of the tibia, a rare tumor of the long bones, revealed a karyotype 52, XY, t(7;13)(q32;q14), +7, +12, +13, +19, +der(7) t(7;13), +der(13) t(7;13). The t(7;13) was found to be constitutional in the patient and was also present in peripheral blood lymphocytes of his unaffected father. However, both subjects displayed normal levels of esterase D enzyme activity.

Banding cytogenetics and fluorescence in situ hybridization analysis of a pulmonary chondroid hamartoma (PCH) showed the presence of a t(6;10)(p21;q22). A cytogenetically identical translocation has previously been found in another case of PCH, suggesting that it could represent a variant form of the standard t(6;14)(p21;q24). Genes Chromosom Cancer 15:246–248 (1996). © 1996 Wiley-Liss, Inc.

Chromosome analysis in short-term lines of three primary and seven metastatic malignant melanomas showed aneuploid karyotypes with recurrent abnormalities of chromosomes 1 (five cell lines), 6 (nine cell lines), and 7 (six cell lines). The breakpoints observed on the rearranged chromosomes frequently coincided with loci of known oncogenes and fragile sites. Two of the cell lines were analyzed after xenograft into nude mice and showed the presence of the same chromosomal changes observed in the parental cell lines, indicating the stability of the karyotype. A tendency toward an increased chromosomal fragility in peripheral blood lymphocytes was observed in five melanoma patients compared to ten normal individuals. However, there was no increased level of expression of specific fragile sites corresponding to the breakpoints observed in melanoma cells.

A cytogenetic analysis was performed on direct preparations and short-term cell cultures of lung tumor and normal bronchial epithelium of 19 patients carrying either a first or a second primary lung cancer. In 9 tumors (6 squamous cell carcinomas, 1 adenocarcinoma, 1 mucoepidermoid carcinoma, and 1 small cell lung carcinoma) successfully analyzed, pseudodiploid and hyperdiploid karyotypes were observed with a heterogeneous pattern of chromosome abnormalities but with a consistent involvement (5 cases) of the short or the long arm of chromosome 3. The normal bronchial epithelial cells had a normal karyotype in 11 patients, whereas in 6 patients clonal and nonclonal chromosomal abnormalities were observed. Involvement of chromosome 7 was present in 4 cases. In addition, overexpression of the growth factor receptors, epidermal growth factor receptor and HER-2/neu, was found in 9 of 18 tumors and in 6 of 13 bronchial epithelium samples. These findings suggest that early genetic lesions could be present in the normal bronchial epithelial cells that are the target of further complex and multiple genetic changes occurring during the pathogenesis of lung cancer.