Atypical melanocytic proliferations and new primary melanomas in patients with advanced melanoma undergoing selective BRAF inhibition.

Abstract

PURPOSE:

Selective inhibition of mutant BRAF by using class I RAF inhibitors in patients with metastatic melanoma has resulted in impressive clinical activity. However, there is also evidence that RAF inhibitors might induce carcinogenesis or promote tumor progression via stimulation of MAPK signaling in RAF wild-type cells. We analyzed melanocytic lesions arising under class I RAF inhibitor treatment for dignity, specific genetic mutations, or expression of signal transduction molecules.

PATIENTS AND METHODS:

In all, 22 cutaneous melanocytic lesions that had either developed or considerably changed in morphology in 19 patients undergoing treatment with selective BRAF inhibitors for BRAF-mutant metastatic melanoma at seven international melanoma centers within clinical trials in 2010 and 2011 were analyzed for mutations in BRAF and NRAS genes and immunohistologically assessed for expression of various signal transduction molecules in comparison with 22 common nevi of 21 patients with no history of BRAF inhibitor treatment.

RESULTS:

Twelve newly detected primary melanomas were confirmed in 11 patients within 27 weeks of selective BRAF blockade. In addition, 10 nevi developed of which nine were dysplastic. All melanocytic lesions were BRAF wild type. Explorations revealed that expression of cyclin D1 and pAKT was increased in newly developed primary melanomas compared with nevi (P = .01 and P = .03, respectively). There was no NRAS mutation in common nevi, but BRAF mutations were frequent.

CONCLUSION:

Malignant melanocytic tumors might develop with increased frequency in patients treated with selective BRAF inhibitors supporting a mechanism of BRAF therapy-induced growth and tumorigenesis. Careful surveillance of melanocytic lesions in patients receiving class I RAF inhibitors seems warranted.

• Authors: Lisa Zimmer, Uwe Hillen, Elisabeth Livingstone, Mario E Lacouture, Klaus Busam, Richard D Carvajal, Friederike Egberts, Axel Hauschild, Mohammed Kashani-Sabet, Simone M Goldinger, Reinhard Dummer, Georgina V Long, Grant McArthur, André Scherag, Antje Sucker, Dirk Schadendorf
• Journal: Journal of clinical oncology : official journal of the American Society of Clinical Oncology (J Clin Oncol) Vol. 30 Issue 19 Pg. 2375-83 (Jul 01 2012) ISSN: 1527-7755 [Electronic] United States
• PMID: 22614973 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Protein Kinase Inhibitors
• BRAF protein, human
• Proto-Oncogene Proteins B-raf

Topics

• Adult
• Aged
• Cell Growth Processes (drug effects)
• Clinical Trials as Topic
• Humans
• Melanoma (drug therapy, genetics, metabolism, pathology)
• Middle Aged
• Protein Kinase Inhibitors (therapeutic use)
• Proto-Oncogene Proteins B-raf (antagonists & inhibitors, genetics, metabolism)
• Signal Transduction
• Skin Neoplasms (drug therapy, genetics, metabolism, pathology)
• Young Adult