{Reference Type}: Case Reports
{Title}: Microsatellite Instability-high Signet Ring Cell Carcinoma of the Colon Treated With Immunotherapy: Report of a Case.
{Author}: Arima K;Uemura N;Tsuneyoshi K;Fujita H;Kuroki H;Uemura S;Hanada N;Baba H;Komohara Y;
{Journal}: Anticancer Res
{Volume}: 43
{Issue}: 10
{Year}: 2023 Oct
{Factor}: 2.435
{DOI}: 10.21873/anticanres.16669
{Abstract}: <B>BACKGROUND: </B>Immune checkpoint inhibitors (ICIs) are attracting increasing attention as a novel and potentially curative therapy for microsatellite instability-high (MSI-H) colorectal cancer (CRC).<BR><B>METHODS: </B>An 80-year-old female visited our hospital with complaints of lower abdominal pain due to bowel obstruction caused by descending colon cancer. After 1 month of metallic stent detention, she underwent radical surgery, although laparotomy showed broad peritoneal dissemination. Based on the genetic finding of MSI-H status, pembrolizumab therapy was administered in two cycles. Unfortunately, the therapy was ineffective, and the patient died after being discharged 5 months after surgery.<BR><B>CONCLUSIONS: </B>The findings in this case of MSI-H CRC with a poor response to an ICI suggest the importance of confirming HLA status, including beta-2-microglobulin and HLA expression, before starting ICI therapy in cases of MSI-H CRC.