Differential Immunoexpression of BRAF/V600E, Senescence Markers, PTEN, and T-type Calcium Channels in Acquired Naevi According to their Histopathological and Dermoscopic Classification

BRAF Immunohistochemical Studies of Pediatric Conjunctival Lesions

PURPOSE

The purpose of this study was to analyze the prevalence of an activating mutation in the B-Raf proto-oncogene (BRAF) V600E immunoreactivity in pediatric conjunctival lesions.

METHODS

This retrospective case-control study included 32 pediatric patients who underwent surgical excision of conjunctival lesions between Jan 2019 and May 2022. The collected data included demographic data, clinical features, and histopathologic characteristics of the lesion, including BRAF V600E positivity. The Student t test and the Fisher exact test were used to determine the significance of the associations between clinical variables and BRAF positivity.

RESULTS

BRAF immunoreactivity was positive in 11/32 lesions (34%). Age at diagnosis did not correlate with BRAF positivity, with a mean age at diagnosis of 131.7 months for patients with BRAF+ lesions and 134.7 months for those with BRAF- lesions ( P > 0.1). No clinical or pathological features were found to be significantly correlated with BRAF positivity, although there was a trend toward BRAF positivity in the presence of cysts ( P = 0.072).

CONCLUSIONS

BRAF reactivity was present in approximately one-third of pediatric conjunctival nevi but does not correlate significantly with unique clinical or histopathological features.

Phenotypic and Dermoscopic Patterns of Familial Melanocytic Lesions: A Pilot Study in a Third-Level Center

Cutaneous melanoma is a highly aggressive skin cancer. It is estimated that 5% to 10% of the underlying mutations are hereditary and responsible for familial (or hereditary) melanoma. These patients are prone to the early development and higher risk of multiple melanomas. In recent years, an increasing number of genes have been identified thanks to genetic testing, allowing the subsequent surveillance of individuals at risk, yet it is still difficult to predict the presence of these mutations on a clinical basis. In this scenario, specific phenotypic and dermoscopic features could help clinicians in their identification. The aim of this work has been to correlate mutations to prevalent dermoscopic patterns, paving the way for reference models useful in clinical practice. In our cohort, out of 115 patients referred to genetic counseling for melanoma, 25 tested positive (21.7%) for critical mutations: CDKN2A (n = 12), MITF (n = 3), BAP1 (n = 1), MC1R (n = 3), PTEN (n = 1), TYR (n = 2), OCA2 (n = 1), and SLC45A2 (n = 2). The phenotype profiles obtained through the digital acquisition, analysis, and description of both benign and malignant pigmented lesions showed a predominance of the type II skin phenotype, with an elevated mean total nevus number (182 moles, range 75-390). As for dermoscopic features, specific mutation-related patterns were described in terms of pigmentation, areas of regression, and vascular structures. Although further studies with larger cohorts are needed, our work represents the beginning of a new approach to the study and diagnosis of familial melanoma, underlining the importance of clinical and dermoscopic patterns, which may constitute a reference model for each gene, enabling comparison.

BRAF V600K vs. BRAF V600E: a comparison of clinical and dermoscopic characteristics and response to immunotherapies and targeted therapies

BACKGROUND

A number of mutations related to malignant melanoma (MM) have been identified, and of the mutated genes, BRAF has been found to be altered in > 50% of cases. Most of these have been BRAF V600E mutations, whereas the incidence of BRAF V600K may vary from 10% to 30%. Little is known about the clinical prognostic correlations of BRAF V600K MMs. We evaluated the clinical and dermoscopic features, incidence, therapy response and outcomes in the medium to long term.

AIM

To compare the clinical and dermoscopic characteristics, the response to systemic therapies and the prognosis among MMs with BRAF V600E and BRAF V600K mutations.

METHODS

We retrieved the data of patients tested in our centre for MM from 2012 to 2015, including clinical features, dermoscopic pictures, clinical history and tumour mutations. Only patients with BRAF V600E and BRAF V600K mutations were included. Any MMs positive for BRAF V600K mutation were collected, and the number of V600K cases and their features were used to extract the same number of patients with BRAF V600E from our database using a matching method. The clinical and dermoscopic presentation, therapy response and disease progression of the two groups were then evaluated.

RESULTS

In total, 132 cases of BRAF V600E-mutated MMs were identified, and then randomized with a propensity-score method to match the 10 retrieved cases of BRAF V600K mutation. Both groups had a nodular appearance to the tumours and an advanced disease stage, and no significant differences in dermoscopic features were highlighted. During the follow-up period, four patients with BRAF V600K died of disease-specific causes. Moreover, we found a higher frequency of metastasis, a faster disease progression and more rapid mortality in patients with BRAF V600K.

CONCLUSION

Despite the small size of this study, the results show similar clinical and dermoscopic characteristics between V600E and V600K mutations, but compared with BRAF V600E MMs, BRAF V600K MMs seem to be less responsive to therapy and have a worse prognosis.