Expression and prognostic analysis of three clones of PD-L1 antibody in colorectal cancer

PD-L1 is a well-established marker in colorectal cancer, whose expression is a crucial indicator for the efficacy of immunotherapy. However, different PD-L1 antibodies showed different results. Our study evaluated the expressions of PD-L1 antibody from three different clones (22C3, SP263, E1L3N) in colorectal cancer tissues, we analyzed and compared their expression consistency in tumor and stroma tissues, as well as investigating the correlation between PD-L1 expression and clinicopathological parameters and patient prognosis. PD-L1 was observed in both tumor cells and immune cells, exhibiting a mottled distribution pattern. Using 1 % as the threshold, the positive rates of CPS for the three clones were 31.5 % (22C3), 28.4 % (SP263), and 32.7 % (E1L3N), respectively. When comparing 22C3 and SP263, as well as SP263 and E1L3N, a high level of consistency was observed. However, moderate consistency was found between 22C3 and E1L3N. The positive rate of CPS in different antibodies was found to be associated with mismatch repair protein (MMR) and lymphatic metastasis, while showing no correlation with gender, age, tumor size, or other parameters. Survival analyses revealed that tumor location, chemotherapy and differentiation degree emerged as independent prognostic factors for patients, whereas there is no significant correlation between PD-L1 expression and overall patient prognosis in colorectal cancer. PD-L1 expression in tumor and immune cells exhibits a variegated and mottled pattern. Three clones of PD-L1 antibody demonstrated moderate to good consistency and potential interchangeability in their expression within colorectal cancer. PD-L1 expression may serve as an indicator of tumor microenvironment in colorectal cancer patients.