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Absence of the c‐Ha‐ ras and c‐Ki‐ ras oncogene mutations in the hermaphroditic fish Rivulus marmoratus papillary thyroid carcinomas induced by N ‐methyl‐ N ′‐nitro‐ N ‐nitrosoguanidine
Author(s) -
Lee J.S.,
Park E.H.,
Choe J.
Publication year - 1999
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1046/j.1439-0426.1999.00130.x
Subject(s) - biology , exon , thyroid carcinoma , carcinogenesis , thyroid , gene , point mutation , microbiology and biotechnology , mutation , cancer research , pax8 , genetics , transcription factor
Previously we reported that papillary thyroid carcinomas were predominantly induced at high frequency by a low dose of N ‐methyl‐ N′ ‐nitro‐ N ‐nitrosoguanidine (MNNG) in the hermaphroditic fish Rivulus marmoratus . In the current study, polymerase chain reaction (PCR) amplification and direct sequencing were used to examine the point mutations of Ha‐ and Ki‐ ras genes, which may be associated with papillary thyroid tumour development in rivulus. Thirty‐three tumour samples were tested, however, no mutations were detected in rivulus Ha‐ and Ki‐ ras genes. In human and rodent models, it has been reported that ras gene mutations in papillary thyroid tumours occurred preferentially in the N‐ ras gene in general, while follicular tumours contained activated Ha‐ or Ki‐ ras gene mutations. This may explain why papillary thyroid carcinomas in rivulus were not mutated at codon 12, 13 or 61 of exon 1 or exon 2 of the rivulus Ha‐ or Ki‐ ras gene. These results imply that another oncogene, such as the N‐ ras gene and others, may be preferentially activated in rivulus papillary thyroid carcinomas, and also give valuable information for comparative studies of papillary thyroid carcinogenesis.