Many tumor types including that of the ovary show loss of heterozygosity (LOH) on chromosome arm 7q, which suggests the existence of at least one tumor suppressor gene (TSG) on this chromosome arm. We have studied the region surrounding the putative tumor suppressor gene CUTL1 at 7q22 in 127 epithelial ovarian tumors. LOH was found across 7q22 in 31% of malignant and 14% of benign ovarian tumors. In 16% of the tumors the LOH appeared to be centered on the CUTL1 gene. This gene has been implicated previously as a TSG in both uterine leiomyomas and breast carcinoma. However, mutation analysis of the CUTL1 gene in 47 tumors with 7q22 LOH failed to identify any somatic alterations in the coding regions. This finding suggests that CUTL1 may not be the target of the 7q22 LOH in ovarian cancers.