DNA replication errors are frequent in mucinous cystadenocarcinoma of the ovary.

To elucidate the genetic etiology of sporadic epithelial ovarian carcinoma, we examined replication errors (RER) in its two common types, serous cystadenocarcinoma (SAC) and mucinous cystadenocarcinoma (MAC). The subjects were 63 patients with sporadic epithelial ovarian carcinoma, consisting of 34 patients with SAC and 29 with MAC. The specimens were formalin-fixed and paraffin-embedded tissues from the ovary. The presence of RER was examined by polymerase chain reaction using 5 microsatellite markers. Of the 61 informative patients with ovarian carcinoma, RERs were observed at greater than or equal to 1 locus in 15 patients (25%). Four of the 32 SAC patients (13%) were RER-positive, and 11 of the 29 MAC patients (38%) were RER-positive, the incidence being significantly higher in the latter than in the former (P < 0.05). The incidence of RER was not related to the patients' age, stage, histologic grade, or prognosis. The MAC patients in stages I and II showed a relatively high incidence of RER (30%). These results suggest that RER are involved in the development and/or progression of MAC among sporadic epithelial ovarian carcinoma in its relatively early stage.