In recent reports, researchers described an increased incidence of cancer in patients with systemic sclerosis (SScl). For this article, the authors investigated the frequencies of cancer in first-degree relatives of patients with SScl in a case-control family study. Information was obtained by personal interview of the probands. Fifty-three subjects with cancer were reported among 814 relatives of patients, compared with 17 subjects among 860 relatives of age- and sex-matched control subjects (age and sex adjusted odds ratio = 3.79, 95% confidence interval = 2.16-6.66, P < 0.001). Forty-six patients (27.7%) had one or more relatives with cancer, compared with 15 control subjects (9%). Within the limitations of the methods used, the researchers found an increased risk for cancer in first-degree relatives of patients with SScl. This suggests that a common genetic or environmental factor may be involved in the development of both cancer and SScl.