Keigo Nishi

Clinical significance of epidermal growth factor (EGF), EGF receptor, and c-erbB-2 in human gastric cancer.

The EGF stimulation system for growth regulation is implicated in normal and neoplastic cell proliferation. The role of EGF, the EGF receptor, and c‐erbB‐2 in human gastric cancer is reviewed on the basis of several reports, which have been mainly oriented toward their clinical significance. EGF has been shown immunohistochemically to be present in 26% of gastric cancers (n = 395). The presence of EGF in gastric cancer is correlated with the degree of gastric wall invasion and lymph node metastasis. The 5‐year survival of patients with EGF‐positive tumors is worse than that of patients with EGF‐negative tumors. The presence of EGF in human gastric cancer may therefore represent a higher malignant potential. Fifteen percent of gastric cancers (n = 352) were also shown to be positive for both EGF and the EGF receptor immunohistochemically, and the simultaneous occurrence of EGF and the EGF receptor suggests that these tumors grow in an autocrine fashion. Tumors exhibiting EGF and the EGF receptor simultaneously show a greater degree of local invasion and lymph node metastasis. Increased expression of EGF receptor protein in gastric cancer appears to be related to biologic aggressiveness, although gene amplification has occurred only to a small extent. Twelve percent of gastric cancers (n = 486) were found to be positive for c‐erbB‐2. This type of tumor has a frequent metastasis, and patients with c‐erbB‐2‐positive cancer have a poorer prognosis than those with c‐erbB‐2‐negative tumors. Selective blockade of the EGF receptor and c‐erbB‐2 from their ligands with monoclonal antibodies (MoAbs) inhibits the growth of human gastric cancer xenografts. These MoAbs may therefore be effective antitumor agents against gastric cancer showing overexpression of EGF receptors or c‐erbB‐2. Cancer 1995;75:1418‐25.

Estrogen and progesterone receptors in gastric cancer.

Cancerous tissue from 86 patients with primary gastric cancer were examined for the presence of receptors for estrogen (ER) and progesterone (PgR). ER and PgR were present in 8 (15.4%) and 5 (9.6%)respectively, of 52 male patients9 (26.6%) and 7 (20.6%)respectively, of 34 female patients, a total of 17 (19.8%) and 12 (14.0%)respectively. One male patient (1.9%) and 4 female patients (11.8%) had both ER and PgR, and 40 male (76.9%) and 22 female patients (64.7%) showed no ER or PgR. The binding activity ranged from 6 to 200 fmol/mg protein for estradiol and from 5 to 58 fmol/mg protein for progesterone. ER‐ and/or PgR‐positive cases were characterized grossly as Borrmann type 4, and microscopically as diffuse type with scirrhous growth pattern. The presence of ER and/or PgR in some gastric cancers indicates the possibility that sex hormonal factors are involved in these tumors.

Immunohistochemical study of intracellular estradiol in human gastric cancer

Tissues from primary human gastric cancers were examined for intracellular estradiol (E2) by using the avidin‐biotin‐peroxidase complex (ABC) immunohistochemical method on formalin‐fixed paraffinembedded sections. Reaction products of E2 were located only in the cytoplasm of the cancer cells, and not detected in noncancerous gastric epithelium. E2‐positive tissues were found in 23 (44.2%) of 52 male patients, seven (20.6%) of 34 female patients and a total of 30 (34.9%) of 86 patients. In male patients, E2‐positive cases occurred without age distinction. In female patients, however, E2 was not found in patients in older age groups, especially patients in the postmenopausal state. Microscopically, E2 was found frequently in intestinal type of cancers in male patients and in cancer with scirrhous growth pattern, in female patients. This is the first report of the demonstration of E2 in gastric cancer. The findings suggest that hormonal factors are involved in gastric cancer, and that the cancers contain endocrinic characteristics.

Immunohistochemical demonstration of epidermal growth factor in human gastric cancer xenografts of nude mice

Thirty‐two surgical specimens and three cell lines of human gastric cancers were used for subcutaneous transplantation into nude mice, resulting in the establishment of eight (25%) xenografts from the surgical specimens and two (67%) from the cell lines. The localization of epidermal growth factor (EGF) in the surgical specimens and cell lines of the gastric cancers and their xenografts in nude mice was then investigated immunohistochemically. Epidermal growth factor was stained in the cytoplasm of the cancer cells, being detected in 16 (50%) of the 32 surgical specimens and in all of the cell lines. Seven (44%) of the sixteen EGF‐positive surgical specimens and one (6%) of the 16 EGF‐negative ones were tumorigenic in nude mice. All of the xenografts in nude mice were positive for EGF. The tumorigenicity of human gastric cancer xenografts in nude mice may, therefore, be correlated with the presence of EGF in cancer cells.

Contrasting Actions of Estradiol on the Growth of Human Gastric Cancer Xenografts in Nude Mice

The effects of estradiol on the growth of six human gastric xenografts in nude mice were studied and diverse effects were found, including one case of stimulation, two of inhibition and three of unchanged condition. Neither the histological features of the original tumor nor the estrogen‐binding capacity seemed to be related to the response to estradiol. It is concluded that the growth of human gastric cancer can be modulated by estradiol.

Simultaneous gastric cancer in monozygotic twins

Monozygotic twins developed gastric cancers that were found almost simultaneously. A 47‐year‐old man complained of nausea and vomiting; an upper gastrointestinal series and endoscopy revealed advanced gastric cancer invading the serosa. Palliative subtotal gastrectomy was performed. In his asymptomatic twin a gastric polyp was detected during a screening examination, and this was observed for 2 years. After the former twin had undergone surgery, the latter twin was given a detailed endoscopic examination, and biopsy revealed gastric cancer limited to within the mucosa. Curative subtotal gastrectomy was performed. The noncancerous gastric mucosa of the former twin showed severe intestinal metaplasia, but that in the latter showed only spotty metaplasia. They had lived together for 40 years, but the former was a heavy smoker and drank alcohol, while the latter did not. These differences in taste might have contributed to the observed difference in intestinal metaplasia, which indicates chronic mucosal damage.

The correlation of epidermal growth factor with invasion and metastasis in human gastric cancer.

We examined the localization of epidermal growth factor (EGF) in 185 specimens of primary human gastric cancer using the avidinbiotin peroxidase complex immunohistochemical method on formalin-fixed paraffin-embedded sections. Thirty-four per cent of the gastric cancer specimens were positive for EGF, which was mainly located in the cytoplasm of the cancer cells and occasionally in the stromal cells, but was not detected in non-cancerous gastric epithelium. Moreover, the presence of EGF in gastric cancer was correlated with gastric wall invasion and lymph node metastasis. EGF was found more often in advanced cancers than in early ones (p<0.01), and also more often in cancers with lymph node metastasis than in those without (p<0.05). The five-year survival of patients with EGF-positive tumors was worse than that of patients with EGF-negative tumors (p<0.05). The presence of EGF in human gastric cancer may thus represent higher malignant potential.

Changes in Serum and Tissue Carcinoembryonic Antigen with Growth of a Human Gastric Cancer Xenograft in Nude Mice

ABSTRACT We established a human gastric cancer xenograft which, when inoculated into nude mice, showed a positive correlation between tumor growth and the serum level of carcinoembryonic antigen (CEA). Serum CEA levels in the mice rose continuously with increasing tumor weight after inoculation, showing a correlation coefficient of 0.96. A positive correlation was also observed between the tissue CEA level and tumor weight, the former increasing along with the latter. Furthermore, the level of serum CEA closely paralleled that of tissue CEA. The serum CEA level fell after tumor extirpation, with a half‐life of approximately 86 h. These results suggest that the elevation of serum CEA is attributable to the gain in tumor weight as well as the increase of CEA production in the tumor tissue. Thus, human gastric cancer xenografts in nude mice are a good model for examining the biological role of CEA.

Correlation between epidermal growth factor receptor concentration and the growth of human gastric cancer xenografts in nude mice

SummarySeven human gastric cancer xenografts with different concentrations of EGF receptor were established in nude mice. The expression of EGF receptor in the tumors was demonstrated by Western blotting with anti-EGF receptor antibody, binding assay with125I-EGF and immunohistochemistry with anti-EGF receptor antibody. Western blotting revealed EGF receptor doublet bands at molecular masses of 150 KDa and 170 KDa in all of the samples. The concentration of125I-EGF binding activity in the tumors ranged from 36.0 to 11,000 fmol/mg protein, with a mean of 345 fmol/mg protein. EGF receptor was also demonstrated immunohistochemically on the apical border of the glands and the cell membrane of the tumor cells. There seemed to be a close correlation between the concentration of125I-EGF binding activity and the doubling time of these tumors in nude mice (γ= -0.68). However, no definite correlation was observed between EGF ligand binding and histological features of intestinal type or diffuse type. The expression of EGF receptor appears to facilitate the growth of human gastric cancer xenografts in nude mice.

[3H]Thymidine autoradiographic and alkaline phosphatase histochemical studies of intestinal metaplasia of the human stomach

SummaryThe relationship between cell proliferation and enzyme activity in intestinal metaplasia of the human stomach was studied using a combined method of [3H]thymidine autoradiography and alkaline phosphatase histochemistry on the same section. Three types of intestinal metaplasia were observed depending on variations in both enzymatic activity and isotope labelling. One type shows alkaline phosphatase-positive cells along the entire length of the glands with [3H]thymidine-labelled cells localized only at the bottom of the glands, resembling the duodenum. In another type of intestinal metaplasia, alkaline phosphatase-positive cells are present on the surface and/or upper half of the glands with mitotically active cells occupying the lower part of the glands. The third variety of intestinal metaplasia is characterized by the absence of alkaline-phosphatase activity and [3H]thymidine-labelled cells present in an extended zone in the lower half of the glands.Differences in labelling patterns of [3H]thymidine and the activity of marker enzyme in various types of intestinal metaplasia seem to reflect variations in cell differentiation during intestinalization of gastric mucosa.