(HealthDay News) – Lymphoid follicles, comprising clusters of B lymphocytes and follicular dendritic cells (DCs) associated with high endothelial venules (HEVs), are found in melanoma metastases, but not in primary melanomas, according to a study published online July 31 in Cancer Research.
Arcadi Cipponi, PhD, from the Université Catholique de Louvain in Belgium, and colleagues investigated whether ectopic lymphoid structures, previously reported in primary lung, breast, and germline cancers, are present in melanoma.
The researchers found that, in seven of 29 cutaneous metastases from melanoma patients, lymphoid follicles, comprising clusters of B lymphocytes and follicular DCs associated with HEVs, and clusters of T cells and mature DCs were observed. Germinal centers were observed in some follicles. Follicles were not seen in primary melanomas but many primary tumors contained HEVs. Clonal amplification, somatic mutation, and isotype switching were revealed on analysis of immunoglobulin genes in the B cells of microdissected follicles.
“Taken together, our findings show the existence of lymphoid neogenesis in melanoma and suggest that the presence of functional ectopic lymphoid structures in direct contact with the tumor makes the local development of antimelanoma B- and T-cell responses possible,” the authors write.