c-Ha-ras BamHI RFLP in human urothelial tumors and point mutations in hot codons

High-molecular-weight DNAs from 30 bladder and renal cell carcinomas (RCC) were isolated and the c-Ha-ras gene BamHI RFLP was examined. Amplification of c-Ha-ras with normal localization with regard to the size of alleles was found only in one case. One of the normally localized c-Ha-ras allele termed RCC c-Ha-ras of a length of about 6.6 kbp was cloned and an oncogene-activating point mutation was identified using two restriction enzymes. After comparison of CfrI and Cfr10I cleavage maps of RCC c-Ha-ras to complete nucleotide sequences of EJ/T24 c-Ha-ras oncogene and its normal counterpart, a point mutation was identified within codon 11 or 12. The use of CfrI and Cfr10I is of value for clinical practice in identification of point mutations in c-Ha-ras PCR product in neoplasia accompanied by somatic mutation of c-Ha-ras. The correlation among c-Ha-ras allele, amplification/loss, presence of point mutation and progression of neoplasia is discussed.