Xd. Zhu et al., Aberrant expression of beta-catenin and mutation of exon 3 of the beta-catenin gene in renal and urothelial carcinomas, PATHOL INT, 50(12), 2000, pp. 945-952
The present study attempted to clarify the significance of aberrant express
ion of beta -catenin protein and mutation of exon 3 of the beta -catenin ge
ne in renal and urothelial carcinogenesis. beta -Catenin expression was exa
mined immunohistochemically and mutation of the beta -catenin gene was anal
yzed by polymerase chain reaction-single strand conformation polymorphism (
SSCP) and direct sequencing. beta -Catenin immunoreactivity was observed at
the cell membrane in all 30 renal cell carcinomas (RCC) examined, and no R
CC showed a mobility-shifted SSCP band. Of 46 transitional cell carcinomas
(TCC) examined, there was reduced expression of beta -catenin, as compared
with its expression in non-cancerous transitional epithelium, in 22 cases (
48%) and beta -catenin accumulation in the nucleus in five cases (11%). Of
four renal pelvis TCC examined, point mutation of exon 3 of the beta -caten
in gene at codon 45 resulting in amino acid substitution (Ser to Phe) was d
etected in one (25%). The incidence of reduced expression of beta -catenin
correlated significantly with the growth pattern (superficial type vs invas
ive type) of TCC (P < 0.05). These data indicate that: (1) aberrant beta -c
atenin expression may be at least partly involved in urothelial carcinogene
sis, but less significantly so in renal carcinogenesis, and (2) it may be a
ssociated with the progression of TCC showing invasive growth.