Halsey Mark A, Calder Kenneth B, Mathew Rahel, Schlauder Scott, Morgan Michael B
College of Medicine, University of South Florida, Tampa, Florida 33604, USA.
J Cutan Pathol. 2010 Apr;37(4):446-51. doi: 10.1111/j.1600-0560.2009.01353.x. Epub 2009 Jul 23.
Alpha-methylacyl-CoA racemase (AMACR), also known as P504S, is a protein that plays an important role in mitochondrial and peroxisomal beta-oxidation of branched-chain fatty acid and bile acid intermediates. AMACR has been established as a valuable diagnostic marker for prostate cancer and has recently been shown to be useful in the diagnosis of colorectal carcinoma. Despite the importance of lipid metabolism in sebum production by sebaceous glands of the skin, there are no studies evaluating the expression of AMACR in sebaceous neoplasms.
Five samples of normal sebaceous glands as well as five cases each of sebaceous hyperplasia (SH), sebaceous adenoma (SA), basal cell carcinoma (BCC) with sebaceous differentiation and extraocular sebaceous carcinoma (SC) were evaluated for immunohistochemical (IHC) expression of AMACR. Each case was reviewed by a single dermatopathologist and graded using a semi-objective grading schema.
Normal sebaceous glands showed strong (4+) expression of AMACR. Among sebaceous neoplasms, SH showed the highest expression (4+), SA and BCC with sebaceous differentiation showed varied expression (2+ and 1+, respectively), and extraocular SC showed no expression of AMACR.
The expression of AMACR is increased in benign sebaceous glands and SH; with decreasing AMACR expression in tumors with less sebaceous differentiation (i.e. SA and SC). These findings provide insight into the potential pathogenesis of sebaceous neoplasms while assisting in the microscopic distinction of SA from SC.
α-甲基酰基辅酶A消旋酶（AMACR），也称为P504S，是一种在支链脂肪酸和胆汁酸中间体的线粒体和过氧化物酶体β-氧化中起重要作用的蛋白质。AMACR已被确立为前列腺癌的一种有价值的诊断标志物，最近还被证明可用于结直肠癌的诊断。尽管脂质代谢在皮肤皮脂腺的皮脂分泌中很重要，但尚无研究评估AMACR在皮脂腺肿瘤中的表达。
对5个正常皮脂腺样本以及5例皮脂腺增生（SH）、皮脂腺腺瘤（SA）、具有皮脂腺分化的基底细胞癌（BCC）和眼外皮脂腺癌（SC）的病例进行AMACR免疫组化（IHC）表达评估。每个病例由一名皮肤病理学家进行复查，并使用半客观分级方案进行分级。
正常皮脂腺显示AMACR强表达（4+）。在皮脂腺肿瘤中，SH显示最高表达（4+），SA和具有皮脂腺分化的BCC显示不同程度的表达（分别为2+和1+），而眼外SC未显示AMACR表达。
AMACR在良性皮脂腺和SH中表达增加；在皮脂腺分化较少的肿瘤（即SA和SC）中AMACR表达降低。这些发现为皮脂腺肿瘤的潜在发病机制提供了见解，同时有助于在显微镜下区分SA和SC。
