PD-L1 Expression in Ampullary Adenocarcinoma

Area of Science:

• Oncology
• Immunohistochemistry
• Cancer Biomarkers

Background:

• Ampullary adenocarcinoma is a rare cancer often treated with the Whipple procedure.
• Prognosis is influenced by histological factors and metastasis.
• Immunotherapy, particularly checkpoint inhibitors, shows promise in various carcinomas.

Purpose of the Study:

• To evaluate the expression of programmed death-ligand 1 (PD-L1) in ampullary adenocarcinoma.
• To determine associations between PD-L1 expression and clinicopathological features.
• To assess the utility of PD-L1 immunohistochemistry (IHC) as a predictive marker.

Main Methods:

• PD-L1 IHC (clone E1L3N) was performed on 101 ampullary adenocarcinoma samples.
• Tumor-infiltrating lymphocytes were also evaluated.
• Immunoreactivity was assessed at various staining thresholds (<1%, <5%, <10%, ≥10% for tumor cells).

Main Results:

• A 10% cut-off for PD-L1 positivity was associated with male patients, older age (>50), and smaller tumor size (<3 cm).
• PD-L1 positivity at this threshold correlated significantly with intestinal differentiation and grade 1 tumors.
• Recurrence was observed in 12 patients, with potential associations noted.

Conclusions:

• PD-L1 IHC clone E1L3N demonstrates positivity in ampullary adenocarcinoma across different thresholds.
• A 10% cut-off for PD-L1 expression shows stronger associations with specific clinicopathological characteristics.
• Further research may elucidate the role of PD-L1 as a biomarker in ampullary adenocarcinoma.