The first observation of the association of Merkel cell polyomavirus and Merkel cell carcinoma in Brazil

Abstract

Background

Merkel cell carcinoma (MCC) is a rare but aggressive primary cutaneous carcinoma with high mortality rates. The present study intends to delineate the epidemiological profile of patients with MCC seen at the Clinics Hospital of the Medical School at the University of São Paulo, Brazil, and its association with Merkel cell polyomavirus (MCPyV).

Methods

This is a retrospective study. A search was performed in the hospital's medical index for all cases of MCC from January 1994 to December 2012. Among patients with MCC, the available tumoral skin specimens were analyzed with two different techniques of polymerase chain reaction (PCR) (conventional and real‐time) for detection of MCPyV DNA. Additionally, paraffin‐embedded samples of patients with non‐MCC skin cancers were also analyzed. Analyses suitable for categorical data (i.e., x² of Fisher) were used to compare the proportion of patients in each group.

Results

Nineteen patients with MCC and 20 patients with non‐MCC skin cancers entered the study. All MCC samples available (13) tested positive for the presence of MCPyV DNA; however, in the non‐MCC skin cancer samples, the MCPyV DNA was detected in 4 of 20 samples (20%). MCPyV DNA detection rate was higher in patients with MCC than in the other group, and its analysis was statistically significant (P < 0.01).

Conclusions

This study demonstrates the association of MCPyV in Brazilian patients with MCC. However, further studies are necessary to determine the exact involvement of MCPyV in MCC pathogenesis and to define the significance of viral DNA detection in non‐MCC skin cancers.

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