Melanoma cell adhesion molecule, Mel-CAM, CD146

This is a cell adhesion molecule

Immunohistochemical expression

It is expressed by a a variety of tissues and tumours and is not a melanoma-specific marker:

• Not by normal melanocytes

• endothelium and its tumors

• Intermediate trophoblast:

  • exaggerated placental site²

  • placental site trophoblastic tumour²

epithelioid melanoma	positive1
desmoplastic/spindle cell melanoma	14/171
clear cell sarcoma	9/10
cellular blue naevus	0/41
melanotic schwannoma	3/31
neurofibroma	4/101
MPNST	3/111
atypical fibroxanthoma	0/10

Diagnostic utility

• As a member of a panel for differentiating between trophoblastic tumour.

References

¹ MB Koch et al. Microphthalmia transcription factor and melanoma cell adhesion molecule expression distinguish desmoplastic spindle cell melanoma from morphologic mimics. Am J Surg Pathol 2001;25:58-64.

² Singer, G., R. J. Kurman, et al. (2002). "HLA-G immunoreactivity is specific for intermediate trophoblast in gestational trophoblastic disease and can serve as a useful marker in differential diagnosis." Am J Surg Pathol 26(7): 914-20.

This page last revised 18.2.2001.

©SMUHT/PW Bishop