Different serotonergic expression in nevomelanocytic tumors

Area of Science:

• Oncology
• Neuroscience
• Dermatology

Background:

• Serotonin (5-hydroxytryptamine; 5-HT) is implicated in tumor progression.
• The role of the serotonergic system in nevomelanocytic tumors requires further investigation.

Purpose of the Study:

• To investigate alterations in the serotonergic system within nevomelanocytic tumors.
• To determine the expression of serotonin, 5-HT1A receptors, 5-HT2A receptors, and the serotonin transporter protein (SERT) in benign nevi, dysplastic nevi, and malignant melanoma.

Main Methods:

• Immunohistochemical analysis of paraffin-embedded biopsies from benign compound nevi (BCN), dysplastic compound nevi (DN), and superficial spreading malignant melanoma (SSM).
• Characterization of 5-HT, 5-HT1A receptors (5-HT1AR), 5-HT2A receptors (5-HT2AR), and SERT expression in tumor cells and surrounding melanocytes.

Main Results:

• Melanocytes surrounding tumors expressed 5-HT1AR and 5-HT2AR.
• DN and SSM tissues showed positive immunostaining for serotonergic markers in suprabasal epidermis, more pronounced in SSM.
• Decreased 5-HT1AR expression at the junctional area in SSM compared to DN and BCN.
• Reduced dermal 5-HT1AR and SERT staining intensity with increasing atypia.
• Increased vessel immunoreactivity for 5-HT2A in SSM versus BCN.
• Tryptase-positive mast cells expressing SERT and 5-HT1AR were observed infiltrating dermal regions of DN and SSM.

Conclusions:

• Alterations in the serotonergic system are associated with nevomelanocytic tumors.
• Mast cells expressing serotonergic markers may contribute to tumor progression in melanoma and dysplastic nevi.