PD-L1 Mainly Expressed in Metastatic CRC Lesions

Overall, 81.8 percent of metastatic CRCs and 40.9 percent of primary lesions had PD-L1 expression

digestive system

MONDAY, Sept. 18, 2017 (HealthDay News) -- Programmed death-ligand 1 (PD-L1) is primarily expressed in metastatic colorectal cancer (CRC) lesions, according to a study published online Aug. 29 in the Journal of Digestive Diseases.

Huanbin Wang, from the Shanghai Jiao Tong University, and colleagues compared PD-L1 expression in primary and metastatic CRC lesions.

The researchers found that PD-L1 expression was significantly more prevalent in metastatic CRCs than in primary tumors, and the PD-L1 expression in primary CRC may not represent the tumors that spread. Overall, 81.8 percent of metastatic CRCs had positive expression of PD-L1, compared with 40.9 percent of primary CRCs (P = 0.012). PD-L1 expression frequently increased during the metastatic process when comparing primary and metastatic lesions of the same patients. However, there was rarely a decrease in PD-L1 expression in metastatic lesions. In both metastatic and primary CRCs, there was intratumoral heterogeneity expression of PD-L1 (28.6 and 33.3 percent, respectively).

"These findings suggest that PD-L1 expression in metastatic CRC should be considered as an independent factor while evaluating the suitability of patients for immunotherapy," the authors write.

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