PDL1 expression in desmoplastic melanoma is associated with tumor aggressiveness and progression.

BACKGROUND: The prognostic role of programmed death ligand 1 (PDL1), CD8, and forkhead box p3 (FoxP3) expression in desmoplastic melanomas is unclear. METHODS: We correlated PDL1, p53, and Ki-67 expression with CD8+ and FoxP3+ immune infiltrates with clinicopathologic variables and patient outcomes in a series of 66 desmoplastic melanomas. RESULTS: Tumoral PDL1 expression (≥25%), which was seen in 21% of patients (14 of 66), significantly correlated with mixed histology, tumor thickness, mitoses, recurrence, and metastasis. According to linear regression analysis, tumoral PDL1 expression correlated with thickness (P = .0041); p53 expression (P = .019); Ki-67 proliferation index (P = .0018); and tumoral CD8 (P = .0084), stromal CD8 (P < .0001), and FoxP3 (P < .0001) T-cell counts. According to univariate analyses, PDL1 expression of 25% or higher correlated with shorter progression-free survival (P < .0001) and melanoma-specific survival (P = .034). According to multivariate analyses, PDL1 expression of 25% or more (P = .026) and mixed histology (P = .039) independently predicted shorter progression-free survival, and presence of lymphovascular invasion predicted shorter overall survival (P = .018). LIMITATIONS: Small study size. CONCLUSION: Tumoral and stromal CD8+ and FoxP3+ lymphocyte counts correlated with tumoral PDL1 expression, which is supportive of an adaptive immune response. PDL1 expression in desmoplastic melanoma was associated with tumor aggressiveness and progression. Although PDL1 expression is typically low in melanoma, its frequency and level of expression in desmoplastic melanoma may identify a subset of melanomas that are likely to respond to immunotherapy.

Melanoma-specific survival is worse in the elderly: a multicentric cohort study.

We aimed to characterise cutaneous melanoma in the elderly and determine its association with poorer prognosis. We studied a prospective cohort of the melanoma population in Catalonia between 2012 and 2016. We compared young patient group (<75 years old) with elderly patient group (≥75 years old). We included 3009 patients (52.5% women) from 14 centres, with a mean age at diagnosis of 61.1 years. In the ≥75-year-old group there was a predominance of men (53.9% vs. 45.5%, P  < 0.001), melanoma was more frequently located in the head and neck area (37.7% vs. 15.5%, P  < 0.001) and lentigo maligna melanoma subtype was significantly more frequent (31.4% vs. 11.6%, P  < 0.001), as were nodular melanoma and acral lentiginous melanoma ( P  < 0.001). In older people, Breslow index, the presence of ulceration and mitotic rate were higher than in younger people. Kaplan-Meier survival curves showed longer melanoma-specific survival (MSS) and melanoma-free survival (MFS) in <75-year-old group compared to the elderly group. Cox regression models demonstrated reduced MSS in patients ≥75 years regardless of gender, location, IB, ulceration and lymph node status at diagnosis (HR 1.54, P  = 0.013) whereas MFS was not independently associated with elderly when head and neck location was considered. Age appears to be an independent risk factor for MSS but not for MFS. Worse melanoma prognosis in elderly could be explained by factors unrelated to the tumour, such as age-related frailty and comorbidities that limit the access to systemic treatments and, eventually, age-related immune dysfunction.