Author: Nat Pernick, M.D. (see Authors page)

Revised: 17 September 2015, last major update September 2013

Copyright: (c) 2003-2015,, Inc.

PubMed Search: ACSM1, Acyl-CoA synthetase medium chain family member 1

  • First discovered in 2001, also called MACS1 (J Biol Chem 2001;276:35961), acyl-CoA synthetase medium-chain family member 1
  • Encodes enzyme catalyzing activation of medium chain length fatty acids (OMIM #614357)
  • Present on chromosome 16p12-13
Clinical Features
Uses by Pathologists
  • Marker of apocrine breast lesions (benign and malignant)
Micro Images

Various normal tissues

Benign breast apocrine lesions

Invasive breast apocrine carcinoma

Kidney tubules

Positive Staining - Normal
Positive Staining - Disease