[Detection of mutation in exon 5 and exon 8 of PTEN in laryngeal squamous cell carcinoma].
OBJECTIVE
To detect mutations of exon 5 and exon 8 of phosphatase and tensin homology deleted on chromosome10/mutated in multiple advanced cancer1/TGF-beta regulated and epithelial cell-enriched phosphatase (PTEN/MMAC1/TEP1 for short PTEN) gene in laryngeal squamous cell carcinoma (LSCC) and analyze the relationship between the mutation and LSCC.


METHODS
Fresh tumor samples from 40 LSCC patients were examined using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and direct DNA sequencing.


RESULTS
The mutation of exon 5 and exon 8 occurred in supra-glottic laryngeal carcinoma and no mutation in the glottic laryngeal carcinoma was found. There were 6 cases of mutation for exon 5, and the mutation rate was 15%. In 2 cases, 1 base pair insertion TT-->TAT in codon 85, while in other two cases, 1 base pair deletion GCA-->GC in codon 86, and the two type mutation may result in frame shift mutation. One case had the above two type mutation simultaneously, which may result in missense mutation; 1 case had 1 base pair insertion TT-->TAT in 85 codon and 1 base pair deletion GCA-->GA, which may result in nonsense mutation. The pathology of 3/6 (50%) cases was low differentiation, and the others (3/6, 50%) were middle differentiation. Five cases had lymphatic metastasis, and the rate of which was 83.3%; the other one had no lymphatic metastasis, and the rate of which was 16.7%. There was only 1 case mutation for exon 8, and the mutation rate was 2.5%. One base pair deletion AAA-->AA in 276 codon as well as 1 base pair insertion CT-->CCT between the 336 codon and 337 codon may result in frame shift mutation. The pathology of the case was low differentiation.


CONCLUSIONS
The codon 85,86 of PTEN gene in exon 5 may be "hot spots" in LSCC and the mutation of PTEN gene may be related with the lymphatic metastasis and middle or low differentiation.
Bai
Wei-liang
WL
Department of Otorhinolaryngology, Second Affiliated Hospital of China Medical University, Shenyang 110004, China. baiweiliang@hotmail.com
Gao
Hong
H
Ren
Zhong
Z
Pan
Zi-min
ZM
D000328:Adult; D000368:Aged; D001483:Base Sequence; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D002879:Chromosomes, Human, Pair 10; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000032:analysis; D005091:Exons / Q000235:genetics; D005260:Female; D016147:Genes, Tumor Suppressor; D006801:Humans; D007822:Laryngeal Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics; D017354:Point Mutation; D018807:Polymorphism, Single-Stranded Conformational; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*
D004273:DNA, Neoplasm; D010744:Phosphoric Monoester Hydrolases; D017027:Protein Tyrosine Phosphatases