Alterations of GPI transamidase subunits in head and neck squamous carcinoma.
BACKGROUND
GPI anchor attachment is catalyzed by the GPI transamidase (GPIT) complex. GAA1, PIG-T and PIG-U are the three of five GPIT subunits. Previous studies demonstrated amplification and overexpression of GPIT subunits in bladder and breast cancer with oncogenic function. We performed an analysis of these subunits in head and neck squamous cell carcinoma (HNSCC).


RESULTS
To evaluate GAA1, PIG-T and PIG-U in HNSCC, we used quantitative PCR (QPCR) and quantitative RT-PCR (QRT-PCR) to determine the copy number of those genes in primary tumors and the matching lymphocytes in 28 patients with HNSCC and quantified RNA expression of those genes in 16 primary HNSCC patients and 4 normal control tissue samples. GAA1 showed a significant increase in normalized mRNA expression, 2.11 (95% CI: 1.43, 2.79), in comparison to that of normal controls, 0.43 (95% CI: -0.76, 1.61), p = 0.014 (Mann-Whitney test). The mean genomic copy number of GAA1 was significantly increased in HNSCC, 0.59 (95% CI: 0.50, 0.79), in comparison to lymphocyte DNA, 0.35 (95% CI: 0.30, 0.50), p = 0.001 (paired t-test).


CONCLUSIONS
An increased expression level and elevated copy number for GAA1 suggest a role for this GPI anchor subunit in HNSCC.
Jiang
Wei-Wen
WW
Department of Otolaryngology- Head and Neck Surgery, Head and Neck Cancer Research Division, Johns Hopkins Medical Institutions, 601 N. Caroline Street, 6th Floor, Baltimore, MD 21287-0910, USA. wwjiang33@hotmail.com
Zahurak
Marianna
M
Zhou
Zeng-Tong
ZT
Park
Hannah Lui
HL
Guo
Zhong-Min
ZM
Wu
Guo-Jun
GJ
Sidransky
David
D
Trink
Barry
B
Califano
Joseph A
JA
D000217:Acyltransferases / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D016022:Case-Control Studies; D002460:Cell Line; D018628:Gene Dosage / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006258:Head and Neck Neoplasms / Q000235:genetics*; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics; D016133:Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
C093316:GPAA1 protein, human; D008562:Membrane Glycoproteins; D000217:Acyltransferases; C081007:COOH-terminal signal transamidase