[Histonet] MITF

[Eddie Martin]

Hi Kathy,

The Journal of Investigative Dermatology had an article in their December 2011 Volume 131 issue 12 on Human Cutaneous Melanomas lacking MITF and melanocyte differentiation. According to the article, Melanomas could be MITF and Melan-A negative, if the Melanomas were TAM tyrosine kinase receptor positive. In this particular study, 38% of the total Cutaneous Melanomas were Axl+ (member of TAM), and none of the Axl+ were MITF and Melan-A positive.

That being said, it may explain why some of your cutaneous melanomas are not MITF positive.  Known internal control tissue for MITF includes epithelioid tissue, mast cells, reactive histiocytes and osteoclasts stain intensely for MITF.  A nevus would also be an ideal control tissue, as would any other perivascular epithelioid tumor.

Best,
Eddie Martin, HTL, HT(ASCP), QIHC