No human virus sequences detected by next‐generation sequencing in benign verrucous skin tumors occurring in BRAF‐inhibitor‐treated patients

Abstract

Patients treated with BRAF inhibitors (e.g. vemurafenib), a novel targeted therapy for advanced melanoma harbouring certain BRAF mutations, develop numerous adverse cutaneous side effects, including skin tumors such as squamous cell carcinoma or non-malignant verruciform keratinocyte proliferations, termed 'BRAF-inhibitor-associated verrucous keratosis (BAVK) lesions'. These keratinocyte proliferations are believed to be caused by paradoxical hyperactivation of the MAPK pathway in cells with wild-type BRAF, but mutated RAS. However, due to the clinical and histological verruca-like appearance of these lesions, additional aetiologic cofactors, such as infectious agents (i.e. oncogenic viruses), might be suspected. Therefore, we performed 454 high-throughput sequencing of BAVK lesions from vemurafenib-treated patients on the transcript level to identify actively transcribed viral sequences of known [e.g. human papilloma viruses (HPV)] or even yet-unknown viruses. Next-generation sequencing did not identify transcripts of any human viruses out of 1 595 161 reads obtained from BAVK lesions of four patients. Nevertheless, all controls were recognized correctly, and the detection of sequences derived from the cutaneous microbiome (e.g. skin commensals and bacterial phages) confirmed the validity and sensitivity of the sequencing data. Our results are consistent with preliminary histological and immunohistochemical findings recently reported by others, who also failed to detect the expression of HPV proteins in BAVK. Although the patient number is limited and we cannot exclude the possibility of having missed a viral transcript of very low abundance, our study argues against a viral aetiology of BRAF-inhibitor-associated verruciform keratoses occurring under vemurafenib.

Cutaneous adverse events in patients treated with BRAF inhibitor-based therapies for metastatic melanoma for longer than 52 weeks

“…Verrucal keratoses are premalignant hyperkeratotic papules that are likely to be precursors to cuSCC in patients treated with BRAF inhibitors. They are very common in the early phase of treatment with monotherapy, occurring in up to 49% of patients . In our population, they were present in 18% of patients after 52 weeks, although this was not statistically significant; likely secondary to a small sample size.…”

Cutaneous Epithelial Tumors Induced by Vemurafenib Involve the MAPK and Pi3KCA Pathways but Not HPV nor HPyV Viral Infection

“…This result is consistent with recent studies suggesting that HPVs are unlikely to be a contributor to VP or SCC tumors. Using next generation sequencing, Ganzenmueller et al could not find HPV in any of the 5 patients with vemurafenib -associated verrucous keratosis lesions (and approximately 20 lesions by patients) [10]. Anforth et al screened HPV in a cohort of six and 10 vemurafenib-induced SCCs and verrucal keratosis, respectively.…”

“…The MAPK pathway has been shown to be an important target for melanoma treatment, and its role in the development of non-melanoma skin cancer has been recently reported [5], [6]. In addition, despite histological similarities with verruca vulgaris, there are conflicting conclusions about the implication of viruses, especially Human Papilloma viruses (HPV), in the development of lesions induced by BRAFi [7]–[10]. Thus, to better understand the mechanisms by which skin tumors develop following BRAFi treatment, we conducted a histological, immunohistological and molecular study to evaluate both the MAPK pathway and the presence of HPV and other polyomaviruses (HPyV), especially Merkel cell polyomavirus (MCPyV), in a group of BRAFi induced VP, KA and SCC.…”

BRAF Inhibitors: Experience in Thyroid Cancer and General Review of Toxicity

“…Because these lesions demonstrate mild epidermal dysplasia 105 , they are treated as precancerous lesions. Verrucous keratoses are not true verruca, as multiple reports have noted that the lesions are negative for human papilloma virus 106,107 . Prompt treatment with cryotherapy, photodynamic therapy, curettage, and/or topical 5-fluorouracil helps prevent both actinic and verrucous keratoses from forming SCC.…”