Alterations of oncogenes in metastatic tumours of human gastric carcinomas

Abstract

(Slamon et al., 1987;Varley et al., 1987), and small cell lung carcinomas (Johnson et al., 1988). Moreover, specific chromosome abnormalities have also been found in a number of human cancers (Yokota et al., 1987;Baker et al., 1989;Lee et al., 1989). However, activation of proto-oncogenes in gastric carcinomas is low compared to colonic and pancreatic carcinomas (Forrester et al., 1987;Smit et al., 1988).Loss of chromosomal heterozygosity is also infrequently found in gastric carcinomas even at chromosomal loci frequently deleted in other tumours, and little is known about genetic changes that are associated with metastasis of gastric carcinomas. We have demonstrated previously that amplification of ERBB and ERBB2 genes is detected in 2.7% and 5.4% of primary gastric carcinomas, respectively (Yoshida et al., 1989 Southern blot analysis High molecular weight DNAs were prepared using the phenol-chloroform method after treatment with sodium dodecyl sulphate (SDS) and proteinase K. DNAs were digested with EcoRI or BamHI, and 10 iLg of completely digested DNAs was electrophoresis on 0.8% agarose gel. After electrophoresis, DNAs were denatured, neutralised and transferred to nitrocellulose filters according to the method of Southern (Southern, 1975). The filters were hybridised under stringent conditions with 32P-labelled probes. After hybridisation, filters were washed and exposed to Kodak XAR-5 films. The same filters were hybridised repeatedly with probes for several oncogenes to exclude the possibility that the difference in the intensities of the bands in different lanes was due to difference in the amounts of DNAs loaded on agarose gels. The levels of amplification were determined by densitometry and the sum of the densitometric signals of all the bands was taken.Slot blot analysis DNAs were extracted from formalin-fixed and paraffinembedded tissues of 20 early gastric carcinomas and one advanced gastric carcinoma whose metastatic tumours had amplification of ERBB2, HST1, and INT2 genes. Sections of 20 Itm in thickness were cut from the blocks using a microtome and these sections were collected. DNAs were extracted following the methods of Goelz et al. (1985) or Dubeau et al. (1986). Ten ILg of the DNA was dissolved in 0.4 M sodium hydroxide, and TE (10 mM tris hydroxymethyl aminomethane and 1 mM ethylene diaminetetraacetic acid (EDTA) pH 7.4) was added to make 50 pAl of the solution. The samples were incubated for 10 minutes at 37°C, treated with an equal volume of 2 M ammonium acetate and applied to a nitrocellulose filter. Filters were baked at 80°C for 2 hours under vacuum. The procedure of hybridisation was the same as that of Southern blot analysis as described above. DNA

Amplification of c-erbB2 proto-oncogene and immunohistochemical expression of c-erbB2 gene product in parathyroid tumors.

“…In this study, the c-erbB2 gene was examined for parathyroid tumors, because this gene was reported to be amplified or expressed in human adenocarcinomas including breast, stomach and pancreas etc. (2,10,13,16,18,22,27). The significance of amplification of this oncogene was controversial.…”

“…In the present study, to clarify whether some parathyroid adenomas have malignant potential, the amplification of the cerbB2 proto-oncogene and the immunohistochemical expression of its product were evaluated in the parathyroid adenoma and adenocarcinoma, because this oncogene has been reported to be amplified or expressed in some adenocarcinomas (2,16,18,22) (Table 2). …”

Gastric Cancer Pathology and Underlying Molecular Mechanisms

“…FGFR2 overexpression proved to be an independent predictive marker of poor survival in one GC study [69], but was not related to prognosis in another GC study [70]. HST-1 (now called fibroblast growth factor 4) was the first oncogene identified in GC in 1986 [71] and was found to be amplified exclusively in metastatic GC [72]. The expression of basic fibroblast growth factor and FGFR was increased more commonly in undifferentiated and scirrhous GC and was associated with larger tumor size and higher stage [73].…”

What Are the Real Roles of Different ErbB Proteins in Barrett’s Esophagus

“…Furthermore, erbB2 is now a target of novel breast cancer treatments with trastuzumab (Herceptin), monoclonal antibodies against erbB2. Expression of erbB2 has also been detected in intestinal and colonic epithelia and gastrointestinal cancers [6][7][8]. Amplification of the erbB2 gene or overexpression of the erbB2 protein has also been reported in gastric adenocarcinoma, correlating with metastasis and survival [9].…”