H-RAS-1 RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM IN NORMAL INDIVIDUALS AND ORAL-CANCER PATIENTS IN INDIA

Restriction fragment length polymorphism (RFLP) of the human H-ras-1 g ene has been indicated as a marker for detection of individuals at hig h risk of cancer. We have investigated the association of RFLP at the H-ras-1 locus and susceptibility to oral cancer by Southern hybridizat ion analysis in 77 primary oral tumors and 99 healthy donors. The freq uency distribution of the BamHI fragments of H-ras-1 revealed homozygo us or heterozygous alleles in the two subpopulations. The heterozygous genotype occurred more frequently in the normal subjects (53%) as com pared to the cancer patients (36%). Four common alleles - Cl to C4, we re noted predominantly in both groups, with rare alleles detected at a lower frequency. The common allele with 7.6 kb BamHI fragment was sig nificantly higher in normals (10%) than in the tumor population (4%) ( P < 0.05). However, a similar distribution of rare alleles in both gro ups indicated that the presence of rare alleles is not indicative of.p redisposition to oral cancer.