H. Nakadaira et al., EFFECTS OF SELENIUM ON GALLBLADDER CARCINOGENESIS INDUCED BY AN INTRACHOLECYSTIC 3-METHYLCHOLANTHRENE BEESWAX PELLET IN FEMALE SYRIAN GOLDEN-HAMSTERS, Cancer letters, 106(2), 1996, pp. 279-285
This study represents the first report of the effects of selenium (Se)
on chemically induced gallbladder carcinogenesis in hamsters. A total
of 100 female Syrian golden hamsters was randomly assigned to four gr
oups, which groups of 25 hamsters were given ad libitum drinking water
containing either 0.0, 0.5, 2.0 or 4.0 ppm Se (as sodium selenite) fo
r 24 weeks. Initiation was performed at week 4 by the insertion of a B
eeswax pellet containing 3-methylcholanthrene (3-MC) into the gallblad
der. The incidence of total malignant tumors at the end of the study (
24 weeks) was 88, 75, 81 and 82% in the 0.0, 0.5, 2.0 and 4.0 ppm Se g
roups, respectively. All the cases of carcinoma but two were considere
d to develop through the sequence from dysplasia to carcinoma in situ
(CIS) and from CIS to adenocarcinoma of invasive type, The incidence o
f CIS was significantly lower in hamsters treated without Se than in t
hose treated with Se (P < 0.05). On the other hand, the incidence of i
nvasive adenocarcinoma was significantly higher in the former than in
the latter (P < 0.05). These results were summarized that Se might ret
ard the progression of hamster gallbladder carcinogenesis induced by a
3-MC beeswax pellet.