The clinicopathological features of programmed death ligand-1 expression in colorectal carcinoma

Abstract

Background Few studies have addressed the clinicopathological features of colorectal cancer (CRC) that express programed death-ligand 1 (PD-L1). Various assays and scoring methodologies were used and thus inconsistent results were obtained. In this study, we aimed to investigate the relationship of PD-L1 expression in CRC with various clinicopathological variables using a standardized assay and scoring algorithm. Design Tissue microarrays were constructed from 91 random cases of CRC diagnosed at King Hussein Cancer Center (KHCC). Immunohistochemical (IHC) staining using the monoclonal antibody 22C3 was performed. Scoring using the standard “Combined Positive Score” (CPS) method was done. CPS of ≥1 was considered positive. Various clinicopathological features were collected from the medical records of the patients. Results Of the 91 cases, 49 (53.8%) were PD-L1 positive (CPS ≥1). PD-L1 expression was more frequent among moderately differentiated carcinomas (43 of 72 (59.7%) were positive compared to 6 of 19 (31.5%) poorly differentiated cases ( P = 0.029)); among node negative cases (21 of 24 (87.5%) N0 cases were PD-L1 positive in contrast to 28 of 67 (41.8%) N1/N2 cases ( P = <0.001)); among mucinous subtype (12 of 15 (80%) of cases ( P = 0.02)); and among mismatch repair deficient (dMMR) (16 of 16 (100%) versus 11 of 30 (36.6%) MMR proficient ( P = <0.001)). Age, gender, localization, and T or M stages were not significantly associated with PD-L1 expression. Conclusion PD-L1 expression in CRC is associated with favorable prognostic features; namely, lower grade, N0, mucinous variant, and dMMR tumors.

PD-L1 evaluation in the gastrointestinal tract: from biological rationale to its clinical application

“…The prognostic impact of PD-L1 expression is controversial in CRC. PD-L1 expression is associated with a better prognosis in some studies 65 , 66 , and with a worse one in others 61 , 73 . A direct impact on overall survival (OS) has not been consistently shown, but some studies have reported a positive correlation between PD-L1 expression and longer disease-free survival (DFS) 67 , 69 .…”

“…There is also controversy whether MSS and MSI CRC differ in PD-L1 expression, with several studies reporting higher percentages (77-100%) of PD-L1 expression in MSI CRC 61 , 64 , 65 , other studies reporting a statistically higher expression of PD-L1 in MSS CRCs 66 , and other contributions reporting no significant differences whatsoever 67 . However, given that several characteristics are shared by MSI and PD-L1 CRCs ( i.e.…”

“…PD-L1 expression has also been reported to be associated with poor tumor differentiation 61 , 63 , 67 , higher T, N and M stages at diagnosis 63 , 67 , 71 , higher tumor budding 67 , 72 , epithelial-mesenchymal transition (EMT) 67 , right-colon tumors 63 , 68 and mucinous 65 , 68 or medullary histology 61 .…”

Low PD‐L1 expression in immune cells predicts the presence of nodal metastasis in early invasive (pT1) colorectal cancer: a novel tool to tailor surgical treatment

“…It should also be noted that the translation of these results into daily practice is hampered by the different scores used for PD‐L1 evaluation [i.e. tumour proportion score (TPS), 18 combined positive score (CPS) 21 or immune cell score (ICS) 19 ], contributing to partially conflicting results 22,23 …”

“…20 It should also be noted that the translation of these results into daily practice is hampered by the different scores used for PD-L1 evaluation [i.e. tumour proportion score (TPS), 18 combined positive score (CPS) 21 or immune cell score (ICS) 19 ], contributing to partially conflicting results. 22,23 Based on this background, PD-L1 expression could represent a surrogate marker of tumour aggressiveness and therefore be associated with nodal metastasis in pT1 CRC.…”