Abstract
BACKGROUND: Endometrial cancer is a common cancer in women, partially linked to defects in mismatch repair function. Besides the well-known mismatch repair proteins, the MLH3 gene may also contribute to cancer susceptibility. CASE PRESENTATION: In this case report, we reported that two related mothers and daughters had mutations in some of their germline genes, with MLH3 as a possible low-risk gene for endometrial cancer, which we further explored as contributing to the development of endometrial cancer. CONCLUSIONS: This case identifies germline heterozygous mutations in two patients, suggesting a potential role for MLH3 in endometrial carcinogenesis, which may act as a low-risk factor to increase the risk of tumor susceptibility and does not rule out the possibility of synergistic increases in pathogenicity with other genes.