# Programmed Death Ligand-1 Expression in Gastric Cancer Cases in Zambia

## TL;DR

This study examines Programmed Death Ligand-1 expression in gastric cancer cases in Zambia and finds it in a small proportion of patients.

## Contribution

The study provides the first assessment of PD-L1 expression in gastric cancer in the Zambian population.

## Key findings

- 14.6% of gastric cancer cases showed positive PD-L1 expression.
- No significant associations were found between PD-L1 expression and clinicopathological variables.
- A small subset of patients may benefit from anti-PD-L1 therapies.

## Abstract

Gastric cancer is a highly fatal disease in Zambia due to delayed diagnosis, aggressiveness of the disease and ineffective treatment. Programmed death ligand-1 is a key biomarker of gastric cancer, linked to immune evasion and response to anti-Programmed death ligand-1 therapies. This study aimed to evaluate the expression of in gastric cancer cases and its association with various clinicopathological prognostic factors in Zambia.

This pilot study utilized archived formalin-fixed, paraffin-embedded tissue blocks from patients diagnosed with gastric cancer at the University Teaching Hospitals in Lusaka, Zambia. A total of 41 gastric cancer samples were examined, with 65.9% female (27) and 34.1% male (14), and a median age of 63 years (interquatile range: 56–76). The slides were stained with Haematoxylin and Eosin, followed by immunohistochemical analysis to assess Programmed Death Ligand-1 expression, which was evaluated using a combined positive scoring system. Statistical analysis was conducted using STATA to evaluate the data version 15.

Six patients (14.6%) exhibited positive expression of Programmed Death Ligand-1, with a combined positive score of 1 or higher. However, our analysis did not reveal any significant associations between PD-L1 expression and any of the clinicopathological variables assessed. We found that a small proportion (14.6 %) of GCs in our population expresses Programmed Death Ligand-1, a potentially therapeutically actionable patient group.