[Incidence of point mutations in Ki-ras codon 12 and 13 in squamous epithelial carcinomas of the head-neck region].
BACKGROUND
Point mutations of ras genes are one of the most frequent genetic alterations in human malignancies with up to over 95% in certain tumors. Some studies have presumed a low incidence of point mutations in Ki-ras gene codons 12 and 13 in squamous cell carcinoma of the head and neck (SCCHN). The objective of this study was to gain more information about the significance of point mutations in Ki-ras codons 12 and 13 by investigation of a high number of cases.


METHODS
By employing the polymerase chain reaction with specific primers, 63 fresh tumor biopsies were investigated by the nonradioisotopic single-strand conformation polymorphism (SSCP) analysis. To cooperate the efficiency and to characterize the nature of the point mutations, direct fluorescence-labeled DNA sequencing was performed in two cases.


RESULTS
Five out of the 63 (7.9%) SCCHN samples exhibited point mutations in codons 12 and 13 by SSCP analysis. In two out of these mutated cases, a G to T transversion in codon 12.2 of the Ki-ras gene was detected. The analysis of the patient's clinical parameters as well as the histopathological grading and tumor staging revealed no correlation with the Ki-ras point mutation.


CONCLUSIONS
Ki-ras point mutations in codons 12 and 13 are a rare event in SCCHN. These data give additional evidence that these genetic alterations do not play a major role in the development of malignancies of the upper aerodigestive tract.
Rathcke
I O
IO
Klinik für Hals-, Nasen-, Ohrenheilkunde, Kopf- und Halschirurgie, Christian-Albrechts-Universität zu Kiel.
Gottschlich
S
S
Görögh
T
T
Lippert
B M
BM
Werner
J A
JA
D000368:Aged; D001706:Biopsy; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D003062:Codon; D005260:Female; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000235:genetics* / Q000473:pathology; D007013:Hypopharynx / Q000473:pathology; D007822:Laryngeal Neoplasms / Q000235:genetics* / Q000473:pathology; D007830:Larynx / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D017354:Point Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011379:Prognosis; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*
D003062:Codon; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras)
Häufigkeit von Punktmutationen in Ki-ras Codon 12 und 13 bei Plattenepithelkarzinomen der Kopf-Hals-Region.