Familial mesothelioma of the pleura--a report of 40 cases.

A survey of 610 pleural mesotheliomas disclosed 40 familial cases. The diagnosis was histologically based in 39 cases, and confirmed by necropsy in 30. Occupational data were collected from the patients or from their relatives by personal interviews. Routine lung sections were examined for asbestos bodies in 32 cases. In 15 cases asbestos bodies were isolated after chemical digestion of lung tissue. Familial mesotheliomas included 31 men and 9 women (age range 44-93 yr, mean 70.7, median 71.0). In 15 families there were blood relations between (or among) the members involved. All the patients had been exposed to asbestos, mostly in the shipyards. Asbestos bodies were found on routine lung sections in 27 cases. Asbestos bodies after isolation ranged from 70 bodies to about 900,000/g dried lung tissue. Latency periods (time intervals between first exposure to asbestos and diagnosis) ranged between 25 and 70 yr (mean 52.0, median 54.0). The occurrence of mesothelioma among subjects with blood relations suggests that genetic factors might play a role in determining the susceptibility to asbestos-related cancer. Familial cases among persons without blood relations raise the question if environmental factors that members of a family share, may act as co-factors in asbestos-related mesothelioma.