The CDKN2A and MAP kinase pathways: molecular roads to primary oral mucosal melanoma

Area of Science:

• Oncology
• Dermatology
• Molecular Biology

Background:

• The origins and development of oral mucosal melanomas remain unclear, with no identified intraoral risk factors.
• DNA repair and cell growth pathways, including CDKN2A and MAPK cascades, are implicated in melanoma development.

Purpose of the Study:

• To investigate the expression of key proteins in the CDKN2A and MAPK pathways in primary oral mucosal melanomas.
• To correlate protein expression with clinical and pathological parameters, including indicators of poor prognosis.

Main Methods:

• Immunohistochemistry was used to examine CDKN2A and MAPK pathway components (RAS, BRAF, MEK1/2, ERK1/2).
• Tissue microarray (TMA) analysis was performed on 35 primary oral mucosal melanoma samples.
• Expression patterns were analyzed and correlated with histological grade, vascular invasion, and metastasis.

Main Results:

• Altered expression of CDKN2A cascade proteins was observed but did not significantly correlate with clinical parameters.
• MAPK pathway protein expression varied, with specific alterations like RAS absence and BRAF/ERK2 positivity linked to adverse features.
• Absence of RAS and ERK1, alongside BRAF and ERK2 positivity, correlated with higher histological grade, vascular invasion, and metastasis.
• MEK2 expression was significantly associated with vascular invasion (P = 0.043).

Conclusions:

• The CDKN2A and MAPK pathways show significant alterations in oral mucosal melanomas, independent of UV exposure.
• Specific protein expression patterns within these pathways serve as important histological indicators of poor prognosis.
• Further research into these pathways is crucial for understanding and potentially targeting oral mucosal melanoma.