Carcinoma of the oral cavity is highly prevalent in India. The majority of these oral cancers are associated with chewing and/or smoking of tobacco and consumption of alcohol. The institution where these authors are based registers 6000 new cancer cases annually. One quarter of these are oral cavity carcinomas. The authors previously reported a pedigree of oral cancer patients registered at their center. The current study compared nonfamilial (sporadic oral cancer patients), unaffected first-degree relatives, and the pedigree families with oral cancer according to constitutional genetic instability through a bleomycin-induced chromosome sensitivity assay.
There were 10 sporadic oral cavity cancer patients, 7 familial oral cancer patients, and 14 unaffected first-degree relatives. Constitutional chromosome abnormalities were not seen in any patients. Spontaneous and bleomycin-induced chromosomal breakage demonstrated a mean b/c value of 1.68 for the familial oral cancer pa-tients, 1.12 in sporadic oral cancer patients, and 0.52 in unaffected family members. Statistical significance was reached between the familial oral cancer patients and the unaffected family members. One unaffected family member with a high b/c value went on to develop oral cavity cancer 18 months following the study.
These authors attempted to identify patients with a genetic predisposition to oral cancer by using a bleomycin chromosomal breakage analysis. Although there was a significant difference between the familial oral cavity cancer patients and their unaffected relatives, there was no difference in those with sporadic oral cavity cancer. The possibility that this test may allow one to determine a particular patient's susceptibility to oral cavity cancer is tantalizing but not yet proven. Further studies need to be done.