Nodular primary cutaneous melanoma is associated with PD-L1 expression

Area of Science:

• Oncology
• Immunology
• Dermatopathology

Background:

• Previous research indicated improved outcomes with anti-PD1 therapy in Stage III melanomas expressing PD-L1.
• PD-L1 (Programmed Death-Ligand 1) is a key immune checkpoint molecule.

Purpose of the Study:

• To investigate PD-L1 expression as a potential biomarker in primary cutaneous melanomas.
• Focus on melanomas in the vertical growth phase.

Main Methods:

• Retrospective analysis of 66 invasive primary cutaneous melanoma cases.
• Immunohistochemical assessment of PD-L1, PD-1, CD3, CD8, and FoxP3 expression in tumor specimens.
• Correlation of PD-L1 expression with clinical and histopathological features.

Main Results:

• PD-L1 expression was detected in 21% of melanomas.
• PD-L1 positivity significantly correlated with increased tumor thickness and nodular melanoma subtype.
• Nodular melanoma was over 6 times more likely to express PD-L1.
• PD-L1 expression correlated with PD-1-expressing tumor-infiltrating lymphocytes.
• No significant association found with patient demographics, tumor site, ulceration, lymph node status, metastasis, or survival.

Conclusions:

• Nodular-type melanoma is associated with PD-L1 expression.
• This association suggests nodular melanomas may be candidates for immunotherapy, particularly adjuvant therapy.