Outpatient clinic for genetic counseling and gene testing of retinoblastoma.

We report on the genetic counseling and gene testing of patients with retinoblastoma who visited the National Cancer Center Hospital, Tokyo, from April 1997 through September 2003. During this period, 73 probands visited the clinic, and gene testing was performed in 51 individuals. Germline mutations of the RBI gene were detected in 20 individuals (39%); the frequencies were 82% (9/11) in bilateral/familial retinoblastoma, 50% (2/4) in unilateral/familial retinoblastoma, 50% (8/16) in bilateral/nonfamilial retinoblastoma, and 5% (1/20) in unilateral/nonfamilial retinoblastoma.

Frequent microsatellite instability in lung cancer from chromate-exposed workers.

Although chromium has been the most extensively investigated metal with respect to mutagenicity and carcinogenicity, its genetic effects in humans are only partly understood. Our previous study demonstrated that lung cancer from chromate-exposed workers infrequently (20%) displayed p53 gene mutations as well as a particular mutation pattern. In the present study, we examined the replication error (RER) and loss of heterozygosity (LOH) in 38 lung cancers from 28 chromate-exposed workers (chromate lung cancer group) and in 26 lung cancer patients without chromate exposure (non-chromate lung cancer group), using six microsatellite markers containing CA repeats: D3S647 (3p23), D3S966 (3p21.