Allelic loss is a hallmark of tumor suppressor gene (TSG) inactivation. We have allelotyped 29 paired lymphoblastoid and lung cancer cell lines derived from 11 patients with small cell (SCLC) and 18 patients with non‐small cell lung carcinomas (NSCLC). Statistical analysis indicated that a threshold of 30% separated non‐random allelic loss from the random genetic deletions of malignancy. We have identified non‐random allelic loss at 42 of 54 (78%) specific chromosomal regions examined, with 22 regions (52%) common between the two major lung cancer histologic types. There were 3 regions (7%) with allelic loss specific for SCLC and 17 regions (41%) specific for NSCLC. Furthermore, there were significant differences in loss of heterozygosity (LOH) frequencies between NSCLC and SCLC at 13 regions on eight chromosome arms (3p, 5q, 6q, 9p, 10q, 11p, 13q, and 19p). Eight homozygous deletions were present in seven cell lines at four regions, 3p12, 3p14.2, 9p21, and 10q23–25. We have also identified novel sites of chromosomal deletions. In particular, there was frequent loss at 11p13 in SCLC and loss at 6p21.3 and 13q12.3 in NSCLC. In this study, we demonstrate that a) non‐random allelic losses in lung cancer involve multiple regions; b) some losses are common to both NSCLC and SCLC subtypes, whereas others are subtype specific; c) there are genetic deletions at novel chromosomal regions; and d) several homozygous deletions have been noted. Our studies demonstrate the usefulness of continuous cell lines for detailed allelotyping, for comparing genetic abnormalities between SCLC and NSCLC, and for identifying homozygous deletions. Genes Chromosomes Cancer 21:308–319, 1998. © 1998 Wiley‐Liss, Inc.

A multifaceted outbreak response was launched to react to an outbreak of syphilis among men who have sex with men. Prompt provider awareness and a preexisting network of HIV/AIDS providers aided case detection. Although the effectiveness of the response could not be scientifically determined, the diverse components of the response were associated with a faster decline in the outbreak than would have been expected. After 3 months, 89 cases had been identified. Outbreak preparedness should include a focus on communities of men who have sex with men, because the reintroduction of syphilis in this population may threaten national efforts toward syphilis elimination.