Little is known about the molecular mechanisms of lung carcinogenesis in women. We initiated an investigation of the role of gender in pulmonary carcinogenesis by analysis of p53 mutations, immunohistochemistry, serum antibodies and c-erbB-2 expression in a series of 63 male and 44 female lung cancer patients whose tumors were resected at the Mayo Clinic between 1991 and 1992. There were 102 smokers and 5 never smoked. Adenocarcinoma was the more frequent histological type in women (62%) than in men (41%). Sequence analysis of exons 5-8 in 42 females and 49 males identified 44 p53 mutations in 42 tumors (46%). Base substitution mutations showed a preponderance of G:C-->T:A transversions, which were more frequent in women than men (40 versus 25%) and in individuals exposed to asbestos. c-erbB-2 immunohistochemical staining was identified more frequently in females (nine cases) than males (two cases). Marked immunohistochemical staining for p53 positively correlated with the presence of missense mutations in exons 5-8 (81%, P < 0.001). Seven missense mutations (four in exon 5, two in exon 6, one in exon 8) were identified in five of nine patients who had serum antibodies recognizing p53; tumors from these patients were also strongly positive for p53 by immunohistochemistry. These and other results indicate gender differences in the genetic and biochemical alterations in lung cancer and generate hypothesis regarding gender differences in lung cancer susceptibility.