RESUMO
Indolent primary cutaneous B-cell lymphoma is a group of malignant lymphomas comprising marginal zone B-cell lymphoma and centrofollicular B-cell lymphoma. Relapse rate of these tumors is close to 40%, and identifying those patients who are likely to progress remains a challenge. The aim of this study was to characterize the microRNA (miRNA) expression profile of a series of primary cutaneous B-cell lymphomas and correlate with histological and clinical findings. We studied a series of 68 patients with primary cutaneous B-cell lymphomas (30 cutaneous marginal-zone B-cell lymphomas and 38 primary cutaneous centrofollicular lymphomas). A set of 11 miRNAs associated with the differentiation stage of B cells was quantified by real-time PCR, using RNA extracted from formalin-fixed, paraffin-embedded tissue diagnostic samples. Relevant clinical variables were retrieved in a subset of 57 patients (28 cutaneous marginal zone B-cell lymphomas and 29 primary cutaneous centrofollicular lymphomas). miR-150 was upregulated in cutaneous marginal zone B-cell lymphomas relative to primary cutaneous centrofollicular lymphoma samples (false discovery rate <0.05). miR-155 and miR-150 expression levels were associated with progression-free survival in a univariate Cox regression analysis (P<0.1). After stratification by histological subtype, low-expression levels of miR-155 and miR-150 were both associated with shorter progression-free survival only in primary cutaneous marginal zone B-cell lymphomas cases (log-rank test, P<0.05). In summary, miRNA expression analysis can be used as a tool for diagnosis and outcome prognosis in indolent primary cutaneous B-cell lymphoma.
