Immunohistochemical and molecular analysis of bax, bcl-2 and p53 genes in laryngeal squamous cell carcinomas.
BACKGROUND
We investigated the role of apoptosis and its potential alterations in laryngeal squamous cell carcinomas (LSCCs) by evaluating bax, bcl-2 and p53 protein expression in 50 cases and by characterising the molecular status of the bax and p53 genes.


METHODS
p53 and bax gene mutations were investigated by means of PCR/SSCP and direct DNA sequencing, and bax, bcl-2 and p53 protein expression by means of immunohistochemistry.


RESULTS
We identified p53 gene mutations in 17/50 cases (34%); p53 expression in 26 of the 50 cases (52%); bcl-2 expression in 5/50 cases (10%); bax expression in 32/47 cases (68%). 18/33 cases with a wild type p53 gene overexpressed p53 protein: 12 cases (approximately 66%) were bax+/bcl-2-. Of the remaining cases without p53 protein expression, seven cases (approximately 47%) were bax+/bcl-2-.


CONCLUSIONS
Our observations suggest that the overexpression of p53 may contribute to the repression of bcl-2 and the induction of bax expression in LSCCs. However, the fact that a number of cases not expressing p53 did not present any clear up-regulation of bax or down-regulation of bcl-2 suggests that bcl-2 and bax may be regulated by various mechanisms other than p53.
Fracchiolla
N S
NS
Laboratorio de Ematologia Sperimentale e Genetica Molecolare, Servizio di Ematologia, Istituto di Scienze Mediche, Milan, Italy.
Capaccio
P
P
Carboni
N
N
Pagliari
A V
AV
Neri
A
A
Ronchett
D
D
Pruner
G
G
Silvotti
M G
MG
Pignataro
L
L
Buffa
R
R
Broich
G
G
D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D005260:Female; D019254:Genes, bcl-2; D016158:Genes, p53; D006801:Humans; D007150:Immunohistochemistry; D007822:Laryngeal Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein