Skin tumors induced by sorafenib; paradoxic RAS-RAF pathway activation and oncogenic mutations of HRAS, TP53, and TGFBR1

Jean Philippe Arnault, Christine Mateus, Bernard Escudier, Gorana Tomasic, Janine Wechsler, Emilie Hollville, Jean Charles Soria, David Malka, Alain Sarasin, Magalie Larcher, Jocelyne Andrë, Nyam Kamsu-Kom, Lise Boussemart, Ludovic Lacroix, Alain Spatz, Alexander M. Eggermont, Sabine Druillennec, Stephan Vagner, Alain Eychène, Nicolas DumazCaroline Robert

Research output: Contribution to journalArticlepeer-review

113 Scopus citations


Purpose: The emergence of skin tumors in patients treated with sorafenib or with more recent BRAF inhibitors is an intriguing and potentially serious event. We carried out a clinical, pathologic, and molecular study of skin lesions occurring in patients receiving sorafenib. Experimental Design: Thirty-one skin lesions from patients receiving sorafenib were characterized clinically and pathologically. DNA extracted from the lesions was screened for mutation hot spots of HRAS, NRAS, KiRAS, TP53, EGFR, BRAF, AKT1, PI3KCA, TGFBR1, and PTEN. Biological effect of sorafenib was studied in vivo in normal skin specimen and in vitro on cultured keratinocytes. Results: We observed a continuous spectrum of lesions: from benign to more inflammatory and proliferative lesions, all seemingly initiated in the hair follicles. Eight oncogenic HRAS, TGFBR1, and TP53 mutations were found in 2 benign lesions, 3 keratoacanthomas (KA) and 3 KA-like squamous cell carcinoma (SCC). Six of them correspond to the typical UV signature. Treatment with sorafenib led to an increased keratinocyte proliferation and a tendency toward increased mitogen-activated protein kinase (MAPK) pathway activation in normal skin. Sorafenib induced BRAF-CRAF dimerization in cultured keratinocytes and activated CRAF with a dosedependent effect on MAP-kinase pathway activation and on keratinocyte proliferation. Conclusion: Sorafenib induces keratinocyte proliferation in vivo and a time- and dose-dependent activation of the MAP kinase pathway in vitro. It is associated with a spectrum of lesions ranging from benign follicular cystic lesions to KA-like SCC. Additional and potentially preexisting somatic genetic events, like UV-induced mutations, might influence the evolution of benign lesions to more proliferative and malignant tumors.

Original languageEnglish
Pages (from-to)263-272
Number of pages10
JournalClinical Cancer Research
Issue number1
StatePublished - 1 Jan 2012
Externally publishedYes


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