Expression of PD-L1 clones (22C3 and 28-8) in hepatocellular carcinoma: a tertiary cancer care hospital experience

Abstract Background Hepatocellular carcinoma (HCC) is a highly aggressive and rapidly progressing form of cancer with a poor prognosis. Recent advances in the management of HCC focused on the novel immunotherapeutic modalities for patients with advanced disease. PD-L1 has emerged as a promising immunotherapeutic approach for HCC. The evaluation of PD-L1 expression aids in identifying patients who can derive maximum benefits from these therapies. This study aims to examine and compare the expression of PD-L1 using two clones (22C3 and 28-8) in HCC patients. Methods Forty-six patients with HCC were selected between 2005 and 2022 from the Shaukat Khanum Memorial Cancer Hospital and Research Centre (SKMCH&RC) in Lahore, Pakistan. The patients' formalin-fixed paraffin-embedded (FFPE) tissue samples were retrieved from the department of pathology to conduct immunohistochemical analysis. Moreover, the clinicopathological data of these patients were gathered from the hospital information system (HIS). To assess the relationship between variables, bivariate analysis was carried out using either the chi-square test or Fisher exact test when necessary. Results Among the 46 tissue specimens analyzed, the presence of clone 22C3 was detected in 20 HCC patients, with 10 patients showing high expression (21.7%) and another 10 patients showing low expression (21.7%). 22C3 expression was not observed in 26 patients (56.5%). On the other hand, clone 28-8 was expressed in 10 patients, all of whom exhibited low expression (21.7%), while no expression of clone 28-8 was observed in 36 patients (78.3%). An association was found between the expression of 22C3 and 28-8 PD-L1 clones (p-value 0.01). Furthermore, upon closer examination, it was revealed that 12 cases exhibited positive results for 22C3 but negative results for 28-8. Interestingly, two cases displayed positive results for 28-8 but negative results for 22C3. Conclusion We obserevd that the PD-L1 clones, 22C3 and 28-8, are comparable. If PD-L1 expression using 22C3 is negative, considering the use of 28-8 for evaluating expression in HCC patients may be beneficial. However, further validation in a larger cohort is necessary.