Identification of Polyomaviruses in Skin Cancers.

BACKGROUND: Polyomaviruses (PyVs) were initially described in animals. They have also been detected in humans with some evidence that could play a role in skin carcinogenesis. OBJECTIVES: This study aimed to verify the presence of PyVs in different skin tumour samples and to make clinical correlations with patients' epidemiological data from Clinics Hospital of Medical School of University of São Paulo, Brazil. METHODS: This is a cross-sectional study. A random selection was performed of 120 patients with histopathological exams of different cutaneous neoplasms equally divided into 6 groups and 20 patients with normal skin. The available skin specimens were analysed with 2 different techniques of PCR (conventional and real time) for detection of PyV DNA. Concomitantly, retrospective analysis of the respective medical records for the collection of epidemiological data was done. Analyses suitable for categorical data were used to compare the proportion of patients in each group. RESULTS: PyV DNA was found in 25.69% of the samples: 15% in basal cell carcinoma group, 15% in squamous cell carcinoma, 28.57% in melanoma, 15% in dermatofibrosarcoma protuberans, 13.33% in Kaposi sarcoma, 65% in Merkel cell carcinoma (MCC), and none in normal skin. Merkel cell PyV detection was statistically significant in MCC patients (p value <0.01), but no correlations were found between PyVs and others skin tumours. CONCLUSION: This study demonstrated the presence of PyVs in different skin tumours; however, no association of any PyVs found in any skin tumour with epidemiological data could be shown. Further studies are still needed to elucidate the mechanisms of PyVs in skin carcinogenesis.

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

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.