Lack of correlation between rare Ha‐ras alleles and urothelial cancer in Japan

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Abstract
Restriction fragment length polymorphism (RFLP) of Haras gene was surveyed by Southern blot analysis in leukocyte DNA from 55 normal individuals and 58 urothelial cancer patients in Japan. Three common alleles and 4 rare alleles were classified. The frequency of common alleles in normal Japanese individuals differed from that in Caucasians previously reported; a 7.2–7.5‐kb Bam HI fragment of common al‐lele wits not observed in Japanese individuals. No significant increase in frequency of the rare Ha‐ras allele was observed in the group of cancer patients. Moreover, no significant different in frequency was observed for the 3 common alleles. Tumor DNA was compared with leukocyte DNA in 30 urothelial cancer patients: in 3 of 8 cases with heterozygous Haras locus, decreased intensity of one band, indicating partial loss of one allele in tumor DNA, was observed. In 3 tumors with either deletion of one Ha‐ras allele or a rare Ha‐ras allele, expression of Ha‐ras gene was examined by Northern blot aralysis. Such genetic alterations did not always result in a marked increase in Ha‐ras expression. These data suggest that tl‐ese genetic alterations are not directly related to Haras expression, and that RFLP of Ha‐ras gene is not a useful genetic marker for urothelial cancer. On the other hand, deletion of one Ha‐ras allele was observed in 1 of 5 cases of bladde‐ cancer and in 2 of 3 cases of renal pelvic cancer, suggesting that that deletion may be important in the development of urothelial cancer.