Cyclin D1 expression in melanocytic lesions of the skin

Progression through the cell cycle is controlled by cyclins, cyclin-dependent kinases, and cyclin-dependent kinase inhibitory proteins. The role of cyclin D1 in the development and progression of melanomas is controversial. The goal of this study is to evaluate the role of cyclin D1 in benign and malignant melanocytic lesions of the skin.

A total of 126 pigmented lesions of the skin including compound nevi (21), intradermal nevi (18), melanoma in situ (28), primary invasive melanomas (30), and metastatic melanoma (29) were evaluated for cyclin D1 expression. The following tiered system was used for scoring: 0% nuclear staining (score 0), 1% to 19% nuclear staining (score 1), 20% to 49% nuclear staining (score 2), and 50% or greater nuclear staining (score 3).

Average scores were significantly higher for primary melanomas compared with nevi and for in situ melanomas compared with primary invasive melanomas. The average score for metastatic melanomas was not significantly different compared with primary invasive melanomas. Scores for primary invasive melanomas did not correlate with depth of invasion or presence of metastases. Compound nevi exhibited a slightly higher level of cyclin D1 expression compared with intradermal nevi.

Although primary melanomas show a higher level of cyclin D1 expression compared with nevi, cyclin D1 appears to have little role in development of a metastatic phenotype. It is not clear why lesions localized near the dermal-epidermal junction express higher levels of cyclin D1. Further studies are indicated to ascertain the biologic role and practical utility of cyclin D1 in melanocytic lesions of the skin.