BRAF V600E mutational load as a prognosis biomarker in malignant melanoma

Analyzing the mutational load of driver mutations in melanoma could provide valuable information regarding its progression. We aimed at analyzing the heterogeneity of mutational load of BRAF V600E in biopsies of melanoma patients of different stages, and investigating its potential as a prognosis factor. Mutational load of BRAF V600E was analyzed by digital PCR in 78 biopsies of melanoma patients of different stages and 10 nevi. The BRAF V600E load was compared among biopsies of different stages. Results showed a great variability in the load of V600E (0%-81%). Interestingly, we observed a significant difference in the load of V600E between the early and late melanoma stages, in the sense of an inverse correlation between BRAF V600E mutational load and melanoma progression. In addition, a machine learning approach showed that the mutational load of BRAF V600E could be a good predictor of metastasis in stage II patients. Our results suggest that BRAF V600E is a promising biomarker of prognosis in stage II patients.This research was supported by the Basque Government (grants ELKARTEK-KK2016-036 and KK2017-041 to MDB, grant IT1138-16 to SA and predoctoral fellowship PRE_2014_1_419 to AS), and by the University of the Basque Country (UPV/EHU) (grant GIU17/066). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Pirin is a prognostic marker of human melanoma that dampens the proliferation of malignant cells by downregulating JARID1B/KDM5B expression

Originally considered to act as a transcriptional co‑factor, Pirin has recently been reported to play a role in tumorigenesis and the malignant progression of many tumors. Here, we have analyzed the diagnostic and prognostic value of Pirin expression in the early stages of melanoma, and its role in the biology of melanocytic cells. Pirin expression was analyzed in a total of 314 melanoma biopsies, correlating this feature with the patient’s clinical course. Moreover, PIR downregulated primary melanocytes were analyzed by RNA sequencing, and the data obtained were validated in human melanoma cell lines overexpressing PIR by functional assays. The immunohistochemistry multivariate analysis revealed that early melanomas with stronger Pirin expression were more than twice as likely to develop metastases during the follow‑up. Transcriptome analysis of PIR downregulated melanocytes showed a dampening of genes involved in the G1/S transition, cell proliferation, and cell migration. In addition, an in silico approach predicted that JARID1B as a potential transcriptional regulator that lies between PIR and its downstream modulated genes, which was corroborated by co‑transfection experiments and functional analysis. Together, the data obtained indicated that Pirin could be a useful marker for the metastatic progression of melanoma and that it participates in the proliferation of melanoma cells by regulating the slow‑cycling JARID1B gene.This project was supported by grants from the Basque Government (KK2017-041 and KK2020-00069 to M.D.B.), the UPV/EHU (GIU17/066 to M.D.B.), H2020-ESCEL JTI (15/01 to M.D.B.) and MINECO (PCIN-2015-241 to M.D.B.). CP holds a predoctoral fellowship from the Basque Government. Part of this project is under European patent No. EP3051291 (EP14796149.4): “Method for diagnosis and prognosis of cutaneous melanoma”, Univer- sity of the Basque Country (UPV/EHU). The authors acknowledge the technical support SGIker resources at the UPV/EHU for the computational calculations, which were carried out in the Arina Informatics Cluster. The authors are grateful to the Basque Biobank for providing the biopsy samples and in particular, to María Jesús Fernández and Arantza Perez Dobaran for their technical support with the immunohistochemistry