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Trisomy of chromosome 9q: Specific chromosome change associated with tumorigenicity during the process of X‐ray‐induced neoplastic transformation in golden hamster embryo cells
Author(s) -
Suzuki Keiji,
Yasuda Naomi,
Suzuki Fumio,
Nikaido Osamu,
Watanabe Masami
Publication year - 1989
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910440620
Subject(s) - biology
We have reported that trisomy of chromosome 7 is commonly observed in anchorage-independent clones isolated from X-irradiated golden hamster embryo cells. All 10 clones derived from different irradiated populations showed tumorigenicity when 1 x 10(7) cells were injected s.c. into nude mice (BALB/c, nu/nu). From karyotypic analysis, we found that 8 of 10 cells showed trisomy of chromosome 9. One cell line had a translocation between chromosomes 9q and 19q and trisomy of chromosome 7. The other cell line contained trisomy of chromosome 9 and a translocation between chromosomes 7q and 8q. Using Southern blot analysis, we observed no amplification of v-myc, v-Ha-ras, v-Ki-ras or N-ras-related oncogenes. Furthermore, we could not detect either an increase in expression of v-myc- and v-Ha-ras-related genes or the activation of any oncogene, by the NIH 3T3 transfection assay. Our results suggest that trisomy of chromosome 7 is insufficient for the expression of tumorigenicity and that increased dosage of chromosome 9q may play an important role in the malignant progression of X-ray-induced neoplastic transformation.