Alpha-methylacyl CoA racemase in pulmonary adenocarcinoma, squamous cell carcinoma, and neuroendocrine tumors: expression and survival analysis.
BACKGROUND
Alpha-methylacyl CoA racemase (AMACR) is an oxidative enzyme involved in isomeric transformation of fatty acids entering the beta-oxidation pathway. AMACR serves as a useful marker in establishing a diagnosis of prostatic malignancy; however, limited information is available in regard to its presence in pulmonary neoplasms.


OBJECTIVE
To investigate AMACR expression within a spectrum of lung carcinomas and its correlation with patients' survival.


METHODS
Four hundred seventy-seven pulmonary carcinomas, including 150 squamous cell carcinomas, 150 adenocarcinomas, 46 typical carcinoids, 31 atypical carcinoids, 28 large cell neuroendocrine carcinomas, and 72 small cell carcinomas, were studied immunohistochemically using tissue microarray-based samples.


RESULTS
Overall, pulmonary tumors were positive for AMACR in a significant percentage (47%) of cases. Among tumor types, 22% of squamous cell carcinoma, 56% of adenocarcinoma, 72% of typical carcinoid, 52% of atypical carcinoid, 70% of large cell neuroendocrine carcinoma, and 51% of small cell lung carcinoma were positive for AMACR. Furthermore, the Kaplan-Meier analysis revealed that the patients with AMACR-positive small cell carcinoma had better survival (19% vs 5% after 5 years, P = .04) than patients with AMACR-negative tumors. Such survival advantage was seen for patients with stage I-II (P = .01) but not stage III-IV small cell carcinomas (P = .58).


CONCLUSIONS
These results indicate that, similar to prostate cancer, the overexpression of AMACR frequently occurs in pulmonary carcinomas. Additionally, its positive correlation with outcome of stage I-II small cell lung carcinoma warrants further investigation of the AMACR role in the prognosis of this tumor.
Shilo
Konstantin
K
Armed Forces Institute of Pathology, Department of Pulmonary and Mediastinal Pathology, 6825 16th St NW, Washington, DC 20306, USA. shilok@afip.osd.mil
Dracheva
Tatiana
T
Mani
Haresh
H
Fukuoka
Junya
J
Sesterhenn
Isabell A
IA
Chu
Wei-Sing
WS
Shih
Joanna H
JH
Jen
Jin
J
Travis
William D
WD
Franks
Teri J
TJ
D000230:Adenocarcinoma / Q000201:enzymology* / Q000401:mortality / Q000556:secondary; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D018278:Carcinoma, Neuroendocrine / Q000201:enzymology* / Q000401:mortality / Q000556:secondary; D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000401:mortality / Q000556:secondary; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000201:enzymology* / Q000401:mortality / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D019998:Racemases and Epimerases / Q000378:metabolism*; D015996:Survival Rate; D046888:Tissue Array Analysis
D014408:Biomarkers, Tumor; D019998:Racemases and Epimerases; C108352:alpha-methylacyl-CoA racemase