Prevalence ofBRAFandNRASMutations and a Comparative Analysis in Primary and Metastatic Melanoma of Korean Patients

Survival rates for invasive cutaneous malignant melanoma in South Korea in accordance with the Eighth edition AJCC Cancer Staging Manual: A retrospective single center study

Background Cutaneous malignant melanoma is known to have a poorer prognosis in Asian patients as compared to Caucasians. Few studies have analysed the overall survival rate (OS) and melanoma-specific survival rate (MSS) of patients with cutaneous malignant melanoma in South Korea. Aim This study aims to analyse the OS, MSS and prognostic factors of patients with invasive cutaneous malignant melanoma in South Korea. Methods The medical records of patients diagnosed with invasive cutaneous malignant melanoma from July 2006 to June 2016 at Kyungpook National University Hospital were reviewed retrospectively. The OS/MSS of these patients were calculated in accordance with the Eighth American Joint Committee on Center staging system and the prognostic factors affecting MSS were analysed. Results A total of 202 patients with a mean age of 61.5 years were included. The 5-year OS/MSS was 64.4%/70.7% in the patients. The 5-year OS/MSS was 94.7%/97.1% for stage I, 67.2%/76.3% for stage II, 54.4%/59.1% for stage III, and 0%/0% for stage IV. On univariate analysis, the age, sex, Breslow thickness, ulceration, microsatellites, satellites, locally recurrent or in-transit metastasis, tumour metastasis in sentinel lymph nodes and clinicopathological stage were all significantly associated with the MSS, but not with acral distribution or BRAF mutation status. However, on multivariate analysis only the Breslow thickness, ulceration and stage IV were significantly associated with the MSS. Limitations This study was conducted retrospectively in a relatively small number of patients at a single tertiary center in South Korea. Conclusions The OS/MSS of patients with invasive cutaneous malignant melanoma in South Korea was lower than those in Caucasians. In addition to the Breslow thickness and ulceration, the impact of tumour location and sentinel nodal metastasis on cutaneous malignant melanoma should be reevaluated to better understand the disease prognosis in these patients.

The frequency and clinicopathological significance of NRAS mutations in primary cutaneous nodular melanoma in Indonesia

BACKGROUND

Melanoma is a lethal skin malignancy with a high risk of metastasis, which prompts a need for research on treatment targets and prognostic factors. Recent studies show that the presence of neuroblastoma RAS viral oncogene homolog (NRAS) mutation can influence cell growth in melanomas. The NRAS mutation, which stimulates the mitogen-activated protein kinase (MAPK) signaling pathway, is associated with a lower survival rate. However, evidence from Indonesia population is still very rare. Further understanding of the role of NRAS mutations in Indonesian melanoma cases will be crucial in developing new management strategies for melanoma patients with NRAS mutations.

AIMS

To explore the frequency of NRAS mutations and their clinicopathological associations in patients with primary nodular cutaneous melanoma in Central Java and Yogyakarta, Indonesia.

METHODS AND RESULTS

Fifty-one paraffin-embedded tissue samples were collected from primary nodular skin melanoma cases between 2011 and 2019 from the two largest referral hospitals in Yogyakarta and Central Java, Indonesia. The NRAS mutation status was evaluated using qualitative real-time polymerase chain reaction (qRT-PCR). The association of NRAS mutation was analyzed with the following: age, gender, location, lymph node metastasis, ulceration, mitotic index, tumor-infiltrating lymphocytes (TILs), necrosis, tumor thickness, lymphovascular invasion (LVI), and tumor size. NRAS mutations were detected in 10 (19.6%) samples and predominantly observed (60%) in exon 2 (G12). These mutations were significantly correlated with lymph node metastases (p = .000); however, they were not associated with other variables analyzed in this study.

CONCLUSIONS

The prevalence of NRAS mutations in primary nodular cutaneous melanoma cases from Indonesia is consistent with previous studies and is significantly associated with increased lymph node metastases. However, the predominant mutation detected in exon 2 (G12) is different from previous studies conducted in other countries. This suggests that melanoma cases in Javanese people have different characteristics from other ethnicities.

Concordance of somatic mutation profiles (BRAF,NRAS, and TERT) and tumoral PD-L1 in matched primary cutaneous and metastatic melanoma samples

Despite the efficacy of BRAF-targeted and PD-L1-related immune therapies in tackling metastatic melanoma, a significant number of patients exhibit resistance. Given this, the objective of the current study was to ascertain concordance of somatic mutations in BRAF/NRAS/TERT and immunohistochemical PD-L1 and CD8 in matched primary cutaneous and metastatic melanoma. A total of 43 archival paired samples with sufficient material for genetic and immunohistochemical analyses met the criteria for inclusion in the study. Immunohistochemistry was performed for PD-L1 and CD8 and direct-DNA Sanger sequencing for BRAF/NRAS/TERT promoter mutational analyses. Agreement between paired samples was assessed using Cohen κ. Poor concordance among primary and corresponding metastases was noted in BRAF (9/42 cases discordant, κ = 0.49; 95% confidence interval [CI], 0.21-0.77; P = .0013), TERT promoter mutations (13/41 cases discordant, κ = 0.33; 95% CI, 0.04-0.62; P = .033), tumoral PD-L1 immunoexpression (9/43 cases discordant, κ = 0.39; 95% CI, 0.07-0.72; P = .0099), and immunoexpression of CD8⁺ T lymphocytes (12/43 cases discordant, κ = 0.44; 95% CI, 0.19-0.69; P = .002). Although NRAS1 and NRAS2 were highly concordant (42/43 and 39/43 cases, respectively), discordant NRAS2 mutational status was associated with a median time to metastasis of 90 versus 455 days for pairs with concordant status (P = .07). Although limited by sample size, our findings suggest that consideration be given to mutational analysis of metastatic tissue rather than the primary to guide BRAF-targeted therapy and question the roles of TERT promoter mutations and PD-L1 as predictive biomarkers in malignant melanoma.