What is HMB45 negative?
Desmoplastic malignant melanoma (DMM) and spindle cell malignant melanoma (SCMM) form a continuum without a discrete separation. One feature characteristic of DMM is a negative reaction for HMB45, a marker for premelanosomes. Fifty-six cases of SCMM were stained with HMB45.
What does HMB45 positive mean?
HMB-45 is a monoclonal antibody that reacts against an antigen present in melanocytic tumors such as melanomas, and stands for Human Melanoma Black. It is used in anatomic pathology as a marker for such tumors.
What does Melan-A positive mean?
Abstract. The presence of Melan-A positive dermal cells in excisions for melanoma in situ represents a frequent conundrum for pathologists. These cells may represent superficially invasive melanoma, benign, incidental, dermal nevi or non-specific staining of dermal melanophages.
What is HMB45 used for?
The anti-melanoma monoclonal antibody HMB45 is widely used in diagnostic pathology owing to its great specificity and sensitivity in identifying pigmented tumors such as malignant melanoma.
What does hmb45 stain?
HMB-45 is a widely used immunohistochemical stain for detection of primary as well as metastatic melanoma (1). Presumably, this method uses monoclonal antibodies to a glycoprotein that is present in premelanosomes (11).
What does HMB-45 stain?
Is there a tumor marker for melanoma?
Two tumor markers are usually used for the monitoring of patients with melanoma, the proteins S100 and melanoma-inhibitory activity (MIA). S100 represents a family of calcium-binding proteins differentially expressed in a large variety of tissues (14).
What is Melan a melanoma?
Melanoma antigen recognized by T cells or Melan-A (MART-1), is a protein with unknown function that is associated with endoplasmic reticulum and melanosomes. Melan A is a sensitive and specific marker for the diagnosis of melanoma.
What is SOX10 melanoma?
SOX10 (Sry-related HMg-Box gene 10) is a key nuclear transcription factor in the differentiation of neural crest progenitor cells to melanocytes. It has been shown to be a sensitive and specific marker of malignant melanoma of multiple histologic types.
Why is HMB 45 negative in angiomyolipoma?
The HMB-45 negativity may be explained by the rarity of the epithelioid cells in these cases, and the HMB-45 positivity is often weaker or absent in spindle cells [9]. In addition, these angiomyolipomas are usually relative small, contrary to what happens to kidney and liver tumors, which are often large.
What is the difference between HMB-45 and actin-SM?
Smooth muscle actin shows positivity in spindled and epithelioid smooth muscle cells. Note the positivity in a vessel wall that acts as an internal control. HMB-45 and Melan-A (MART-1) show stronger expression in epithelioid areas, while actin-sm is positive in spindled cells.
What is the role of HMB-45 in the pathogenesis of melanoma?
HMB-45 can be expressed in the intraepidermal component of compound nevi and superficial stromal melanocytes 49 but is largely negative in the subepithelial component in comparison to malignant melanoma. Malignant melanoma usually shows diffuse HMB-45 staining with increased atypical melanocytic cells in cycle with Ki-67 staining.
What is rapidrapid HMB-45 staining?
Rapid HMB-45 staining has been used to aid in the interpretation of frozen sections during Mohs surgery in the treatment of melanoma. 1944 Both HMB-45 and NKI/C3 are expressed in a small number of breast carcinomas. 1945 HMB-45 appears to stain melanosomes early in their formation, but not late (stage IV) melanosomes.