HMB-45 is a

monoclonal antibody A monoclonal antibody (mAb, more rarely called moAb) is an antibody produced from a cell Lineage made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell. Monoclonal antibodies ca ...

that reacts against an antigen present in

melanocytic Melanocytes are melanin-producing neural crest-derived cells located in the bottom layer (the stratum basale) of the skin's epidermis, the middle layer of the eye (the uvea), the inner ear, vaginal epithelium, meninges, bones, and heart. ...

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

s such as

melanoma Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...

s, and stands for Human Melanoma Black. It is used in

anatomic pathology Anatomical pathology (''Commonwealth'') or Anatomic pathology (''U.S.'') is a medical specialty that is concerned with the diagnosis of disease based on the macroscopic, microscopic, biochemical, immunologic and molecular examination ...

as a marker for such tumors. The specific antigen recognized by HMB-45 is now known as Pmel 17.

History

HMB-45 was discovered by Drs. Allen M. Gown and Arthur M. Vogel in 1986. The antibody was generated to an extract of melanoma.

Cancer diagnostics

In a study to determine diagnostic usefulness of specific antibodies used to identify melanoma, HMB-45 had a 92% sensitivity when used to identify melanoma. The antibody also reacts positively against junctional

nevus Nevus (plural nevi) is a nonspecific medical term for a visible, circumscribed, chronic lesion of the skin or mucosa. The term originates from ''nævus'', which is Latin for "birthmark"; however, a nevus can be either congenital (present at bir ...

cells and fetal melanocytes. Despite this relatively high sensitivity—HMB-45 does have its drawbacks. HMB-45 can be detected in only 50-70% of melanomas. HMB-45 does not react well against intradermal nevi, normal adult melanocytes, spindle cell melanomas and desmoplastic melanomas. HMB-45 is nonreactive with almost all non-melanoma human malignancies, with the exception of rare tumors showing evidence of melanogenesis (e.g., pigmented

schwannoma A schwannoma (or neurilemmoma) is a usually benign nerve sheath tumor composed of Schwann cells, which normally produce the insulating myelin sheath covering peripheral nerves. Schwannomas are homogeneous tumors, consisting only of Schwann cells. ...

, clear cell

sarcoma A sarcoma is a malignant tumor, a type of cancer that arises from transformed cells of mesenchymal (connective tissue) origin. Connective tissue is a broad term that includes bone, cartilage, fat, vascular, or hematopoietic tissues, and sarcom ...

) or tumors associated with

tuberous sclerosis Tuberous sclerosis complex (TSC) is a rare multisystem autosomal dominant genetic disease that causes non-cancerous tumours to grow in the brain and on other vital organs such as the kidneys, heart, liver, eyes, lungs and skin. A combination ...

complex (

angiomyolipoma Angiomyolipomas are the most common benign tumour of the kidney. Although regarded as benign, angiomyolipomas may grow such that kidney function is impaired or the blood vessels may dilate and burst, leading to bleeding. Angiomyolipomas are st ...

and lymphangiomyoma).

Storage

HMB-45 should be stored at 4 degree Celsius. At 4 degrees Celsius the antibody will be stable for up to 2 months without any loss of quality. For best results it should be used before the expiration date.

Alternatives

When conducting an immunocytochemical studies to identify melanoma for scientific or clinical studies, scientist and medical professionals can also use S-100,

Melan-A Protein melan-A also known as melanoma antigen recognized by T cells 1 or MART-1 is a protein that in humans is encoded by the ''MLANA'' or "MALENA" gene. A fragment of the protein, usually consisting of the nine amino acids 27 to 35, is bound by ...

Tyrosinase Tyrosinase is an oxidase that is the rate-limiting enzyme for controlling the production of melanin. The enzyme is mainly involved in two distinct reactions of melanin synthesis otherwise known as the Raper Mason pathway. Firstly, the hydroxylat ...

, and

Mitf Microphthalmia-associated transcription factor also known as class E basic helix-loop-helix protein 32 or bHLHe32 is a protein that in humans is encoded by the ''MITF'' gene. MITF is a basic helix-loop-helix leucine zipper transcription factor ...

to identify tumors.

References

External links