Increased spontaneous and mitomycin C-induced sister chromatid exchanges in patients with cancer of the cervix uteri, with special reference to stage of cancer.

The frequencies of spontaneous and mitomycin C (MMC)-induced sister chromatid exchange (SCE) were examined in 35 patients with cancer of the cervix uteri (stage 0, eight cases; stage I, nine cases; stage II, nine cases, and stage III, nine cases) before they had undergone cancer treatment, as well as in seven patients with uterine myoma and 18 healthy women as controls. The frequency of SCE was analyzed in reference to the stage of cancer in the cancer group and in reference to chromosome group in the cancer and normal groups. The frequencies of spontaneous and MMC-induced SCE in the cancer group were 10.0 +/- 1.8 and 20.7 +/- 2.6, respectively, and both were significantly higher than in the myoma (8.1 +/- 0.8 and 17.6 +/- 1.8) and normal (7.6 +/- 0.8 and 17.6 +/- 2.3) groups. Furthermore, the frequency of SCE in the cancer group increased with cancer stage. All chromosome groups contributed equally to the increase in SCE in the cancer group. These results indicate that an increase in the frequency of SCE in patients with cervical cancer is related to the presence of cancer, but is not related to a predisposition to cancer.