Research progress of MSI-CRC on anti-PD-1 therapy / 国际外科学杂志

The programmed cell death receptor 1 (PD-1) antibody has been used in the treatment of a variety of malignant tumors, in which colorectal cancer is considered immune " cold" tumor and is not sensitive to anti-PD-1 therapy. The molecular characteristics of mismatch repair deficient (dMMR)/high microsatellite instability (MSI-H) are important molecular markers for screening patients with immune checkpoint inhibitors therapy (ICIs). However, only some patients can benefit from ICIs treatment, and some patients even have disease progression. This article summarizes the research progress of anti-PD-1 immunotherapy of MSI-CRC in recent years, including the mechanisms of resistance, new efficacy biomarkers and treatment options, so as to provide ideas for expanding the application of immunotherapy in colorectal cancer.

Mismatch repair protein deficient endometrioid adenocarcinomas, metastasizing to adrenal gland and lymph nodes: Unusual cases with diagnostic implications.

Recently, certain endometrial carcinomas have been found to be associated with mismatch repair (MMR) protein defects/deficiency. A 39-year-old female presented with cough, decreased appetite and significant weight loss since 2 months. Earlier, she had undergone total abdominal hysterectomy with bilateral salpingo-oophorectomy (TAH-BSO) for endometrioid adenocarcinoma. Imaging disclosed an 8 cm-sized adrenal mass that was surgically excised. Histopathology of the adrenal tumor, endocervical tumor, and endometrial biopsy revealed Federation of Gynecology and Obstetrics (FIGO) Grade II to III endometrioid adenocarcinoma. By immunohistochemistry, tumor cells were positive for cytokeratin 7, epithelial membrane antigen, PAX8, MLH1 and PMS2 while negative for estrogen receptor (ER), progesterone receptor (PR), MSH2 and MSH6. She underwent adjuvant radiotherapy and chemotherapy. A 34-year-old lady presented with vaginal bleeding since 9 months. She underwent TAH-BSO, reported as FIGO Grade III endometrioid adenocarcinoma. By immunohistochemistry, tumor cells were negative for ER, PR, MLH1, and PMS2 while positive for MSH2 and MSH6. She underwent adjuvant radiotherapy and chemotherapy. However, she developed multiple nodal and pericardial metastases and succumbed to the disease within a year post-diagnosis. Certain high-grade endometrioid adenocarcinomas occurring in younger women are MMR protein deficient and display an aggressive clinical course. Adrenal metastasis in endometrial carcinomas is rare.