Kim M, et al. J Gastric Cancer. 2022 Oct;22:e35. https://doi.org/10.5230/jgc.2022.22.e35

Background: Human papillomavirus (HPV) infection is a major cause of cervical cancer and associated precursor lesions. Multiple HPV genotype infections have been reported. However, their clinicopathological characteristics still remain elusive.Methods: For this study, 814 consecutive patients who had undergone colposcopy and HPV genotyping test using BD Onclarity HPV assay were retrospectively selected. Clinicopathological parameters of multiple HPV infections were compared with those of single HPV infection.Results: Multiple HPV infections were found in 110 out of 814 cases (13.5%). Multiple HPV infections were associated with a significantly higher incidence of high-grade intraepithelial lesions (HSILs) compared with single HPV infection. Other high-risk HPV genotypes, in addition to HPV 16, were found more frequently in the multiple HPV infections group; these included HPV 51, 52, 33/58, 56/59/66, and 35/39/68. No specific coinfection pattern was not identified. Additionally, the number of HPV genotypes in multiple HPV infections was not associated with the progression to HSIL or squamous cell carcinoma.Conclusions: Multiple HPV infections have distinct clinicopathological characteristics (compared with single HPV infection). As their biological behavior is uncertain, close and frequent follow-up is warranted.

Nivolumab plus chemotherapy in the first-line setting has demonstrated clinical efficacy in patients with human epidermal growth factor receptor 2–negative advanced or metastatic gastric cancer, and is currently indicated as a standard treatment. Programmed death-ligand 1 (PD-L1) expression is an important biomarker for predicting response to anti–programmed death 1/PD-L1 agents in several solid tumors, including gastric cancer. In the CheckMate-649 trial, significant clinical improvements were observed in patients with PD-L1 combined positive score (CPS) ≥ 5, determined using the 28-8 pharmDx assay. Accordingly, an accurate interpretation of PD-L1 CPS, especially at a cutoff of 5, is important. The CPS method evaluates both immune and tumor cells and provides a comprehensive assessment of PD-L1 expression in the tumor microenvironment of gastric cancer. However, CPS evaluation has several limitations, one of which is poor interobserver concordance among pathologists. Despite these limitations, clinical indications relying on PD-L1 CPS are increasing. In response, Korean gastrointestinal pathologists held a consensus meeting for the interpretation of PD-L1 CPS in gastric cancer. Eleven pathologists reviewed 20 PD-L1 slides with a CPS cutoff close to 5, stained with the 28-8 pharmDx assay, and determined the consensus scores. The issues observed in discrepant cases were discussed. In this review, we present cases of gastric cancer with consensus PD-L1 CPS. In addition, we briefly touch upon current practices and clinical issues associated with assays used for the assessment of PD-L1 expression in gastric cancer.