Gastric cancer heterogeneity

This study was carried out on 222 samples from 37 gastric carcinomas to assess the incidence of multiple stem lines in primary tumors and metastasis as reflected by multiple DNA stem lines and their relationship to epidermal growth factor (EGF) receptor expression, histologic grade, tumor size, and degree of wall infiltration. Fifteen primary tumors (40.5%) were homogeneously diploid/peridiploid whereas 22 (59.5%) were aneuploid. In the lymph node metastasis, seven patients (29.2%) had an homogeneous diploid/peridiploid pattern in all metastatic lymph nodes. On the other hand, 17 (70.8%) had at least one aneuploid peak in the lymph node metastasis. DNA content heterogeneity was seen in 12 (33%) of primary tumors whereas 14 (66.6%) of 21 patients had multiple cell clones in the metastasis. Therefore, 12 patients had a metastatic clone which was not observed in the primary tumor. DNA content heterogeneity was seen even in tumors with submucosal invasion suggesting that this phenomenon is also present at earlier stages. No correlation between the histologic grade and the DNA distribution was observed. Furthermore, histologic heterogeneity was independent of DNA content heterogeneity. The EGF receptor expression was observed in six of the 23 patients in whom this analysis was done. The EGF receptor expression was constant in all samples which were studied and even samples with a different DNA content and histologic grade were stables for the EGF receptor expression.

Distribution of fibronectin and laminin in early and advanced signet-ring-cell carcinomas of the stomach

An immunoperoxidase method was used to compare the distribution of fibronectin and laminin between superficially spreading and deeply infiltrating parts of signet-ring-cell carcinoma of the stomach. In both parts, laminin-containing basement membranes were generally scarce, but they were observed on some of the cancer cells which had differentiated to glandular cells. Intramucosal invasion fronts of superficially spreading cancers often showed a layered structure, consisting of a middle zone of small cancer cells together with a superficial and a deep zone of signet-ring cells. In this structure, linear fibronectin and laminin deposits were common on the cancer cells in the deep zone, but rare in the superficial zone. However, fibrillar fibronectin deposits in the stroma were not considerably larger in either zone. At extramucosal invasion fronts of deeply infiltrating (advanced) cancers, a stromal remodelling with an increased amount of fibrillar fibronectin deposits was often observed around the cancer cells, whose cell surface fibronectin was largely lost even from some basement membranes. These findings suggest that invasive activity of signet-ring-cell carcinoma may not be related to the mere presence or absence of cell-surface fibronectin and laminin but to the amount of stromal fibronectin, which could reflect a cell-stroma interaction. Signet-ring-cell carcinomas have a stage of intramucosal growth in which cancer cells may live in dependence upon the pre-existing stroma and form the layered structure, while in advanced stages cancer cells seemed to have acquired an ability to elicit their own "tumor stroma".

[X-ray fluorescent determination of iron, copper, zinc, bromine and rubidium in biopsies of the gastric mucosa]

A method of a combined use of fiber gastroscopy and x-ray fluorescent analysis was elaborated for a study of the chemical composition of the gastric mucosa. Fr, Cu, Zn, Br, and Rb concentrations were determined in gastric mucosa biopsy specimens obtained during fiber gastroscopy, using x-ray fluorescent analysis. The concentrations of trace elements in the gastric mucosa were determined in 13 healthy persons, in 23 patients with chronic mucosal atrophy, in 15--with gastric ulcer, and in 16--with polyps. Besides, the content of trace elements was determined in the tumorous tissue of 66 gastric cancer patients. The results of the investigation revealed a statistically significant rise of mean Fr concentrations on the ulcer edge, in polyps and tumorous tissue as compared to the unchanged mucosa. Polypous tissue differed from the normal gastric mucosa by a low level of Cu, the difference being statistically significant. A tendency to a decrease in Zn content as compared to the unchanged mucosa was noted in the edge of ulcerative defects. The method can be effectively used for intravital studies on Fr, Cu, Zn, Br, and Rb levels in the G. I. tract mucosa.

Coincidence of fundic glandular hyperplasia and carcinoma of the stomach

Eight patients with stomach cancer are described who had also a striking glandular hyperplasia of the fundic mucosa adjacent and remote from the tumor. Five of the eight patients were young women (30 to 37 years of age). The tumors were poorly differentiated carcinomas and six of the eight patients have died of their disease. None of the patients had clinical evidence of endocrine dysfunction including the Zollinger-Ellison syndrome. Immunohistochemistry revealed cells with endocrine differentiation in five of eight tumors, and in two tumors gastrin producing cells were found. Five of seven patients showed increased numbers of antral G-cells. In two patients numerous endocrine (chromogranin-positive) cells were present in the fundic mucosa, specific products of which could not be identified with the antigens tested. No satisfactory explanation exists for this coincidence and its apparent predominance in young female patients. It may be that endocrine substances are responsible for this fundic hyperplasia and that they may also act as promotors of tumor growth.

Gastric carcinoma with lymphoid stroma. Analysis using mucin histochemistry and immunohistochemistry

A total of 626 surgically resected gastric carcinomas were reviewed, and 24 cases (3.8%) of "gastric carcinoma with lymphoid stroma" were identified. The tumour cells were consistently arranged in an anastomosing trabecular or alveolar pattern and were densely infiltrated by lymphoid cells. The specimens were studied using mucin histochemistry and the indirect immunoperoxidase method to determine the histochemical properties of this form of gastric carcinoma. The tumour cells were consistently positive for concanavalin A paradoxical staining, class III and almost devoid of acidic mucins, features demonstrating preferential differentiation toward pyloric glands or pseudopyloric glands. Immunohistochemically, positive reactions for Leu M1 and lysozyme, marker substances of (pseudo)pyloric gland cells, were often observed. Carcinoembryonic antigen was positive in focal areas without (pseudo)pyloric glandular patterns. Secretory component was focally positive. HLA-DR was strongly expressed in most cancer cells and 17 tumours (71%) showed positivity for interleukin 1 (IL-1). The lymphoid stroma contained a high percentage of UCHL1-reactive T cells both within and around the cancer cell nests, while SL26-reactive B cells clustered in lymphoid follicles. A considerable number of T-lymphoid cells were also reactive for IL-1. A number of plasma cells with a predominance of IgG-type were distributed around the cancer cell nests. S-100 protein-positive dendritic cells were not identified. We speculate that the prominent lymphoid stroma including intraepithelial lymphocyte-like T cells with IL-1 receptors is possibly induced by IL-1 related mediators released from the HLA-DR-positive gastric cancer cells of the (pseudo)pyloric gland-type.

Epithelial markers in synovial sarcoma. An immunohistochemical study on paraffin embedded tissues

Immunohistochemical studies on synovial sarcomas have proved the potentiality of these neoplasm for epithelial and mesenchymal differentiation and antibodies detecting epithelial cells have been found to be helpful in determining the histological types. In this study different epithelial markers directed against various cytokeratins, HMFG-2 and EMA were investigated on paraffin embedded tissues of 13 cases of synovial sarcomas, with regard to their reliability in unmasking the epithelial components demonstrable in this type of neoplasm. The results lead to three conclusions: firstly, synovial sarcomas possess the capacity for generating different epithelial cell types with uncommon compositions of intermediate filaments as well as of membrane proteins, secondly, these features may be expressed in a heterogenous pattern even within the same tumour and finally, the use of wide range anti-cytokeratin antibodies covering the spectrum of basic as well as acidic type proteins seems to be necessary for the detection of all epithelial components demonstrable in synovial sarcomas.

Immunohistochemical study of ras p21 expression in human gastric cancers and benign lesions

Expression of ras p21 in human gastric cancers, benign lesions and normal tissues was immunohistochemically evaluated by the avidin-biotin peroxidase complex (ABC) method with anti-ras p21 monoclonal antibody rp-28. Positive p21 immunoreactivity was shown in 23 (77%) of 30 gastric cancers, in 13 (48%) of 27 benign lesions and in 10 (22%) of 46 normal mucosa cases. Among them, strong staining was demonstrated only in 11 (37%) of 30 gastric cancers, but not in benign lesions and normal tissues. Cases showing more than 20% positive cell ratio were observed in 22 (73%) gastric cancers, in 11 (41%) benign lesions and 6 (13%) normal mucosa cases. Further, intracellular distribution of ras p21 is heterogeneous in gastric cancers, while it is homogeneous in benign lesions or normal tissues. The ABC method with rp-28 could be helpful for clinical differential diagnosis between gastric cancers and benign lesions by investigating three factors: staining intensity, positive cell ratio and intracellular distribution of ras p21.

Epidermal growth factor receptor status and S-phase fractions in gastric carcinoma

The correlation with epidermal growth factor (EGF) receptor expression and clinicopathologic findings were studied in 242 gastric carcinomas. They were stained for EGF receptor by means of an immunohistochemical technique using a monoclonal antibody against the receptor. S-Phase fractions were measured by in vivo bromodeoxyuridine (BrdU) labeling and indirect immunohistochemical staining using anti-BrdU monoclonal antibody. In normal gastric epithelium, EGF receptor immunoreactivity could not be found. EGF receptor was found in 76 (31.4%) of 242 gastric carcinomas. Diffusely infiltrating types of carcinomas were more likely than localized tumors to be EGF receptor-positive. In addition, EGF receptor-positive tumors had significantly higher values of BrdU labeling indices than EGF receptor-negative tumors. The patients with EGF receptor-positive carcinomas also had a poorer prognosis than did negative cases. These results suggested that EGF receptor-positive tumors may have higher proliferative activity and local extension may progress more rapidly, and also seem to show that EGF receptor status may possibly be a useful prognostic marker for gastric carcinomas.

Measurement of urinary trypsin inhibitor in urine, plasma and cancer tissues of patients with stomach cancer

Antiserum was obtained from rabbits immunized with a highly purified preparation of urinary trypsin inhibitor (UTI) conjugated with rabbit serum albumin. Anti-UTI antibody did not cross-react with antibody against inter-alpha-trypsin inhibitor (I alpha I) as determined by immunodiffusion against human plasma. A highly sensitive enzyme immunoassay was developed for the determination of UTI-related antigens (UTIR) in plasma, urine and cancer tissues. The level of UTIR correlated with UTI activity in urine. UTIR levels in urine and plasma did not change with age, but UTIR levels were higher in the stomach cancer tissue than in the surrounding stomach mucosa. UTIR levels did not correlate with I alpha I levels in the plasma of patients with stomach cancer, thus the increase was not considered due to the contamination of circulating I alpha I in the cancer tissues.

[A new chemosensitivity test for cancer cells by measuring intracellular ATP content]

Several in vitro chemosensitivity tests have been developed to select effective anticancer agents for individual cases. However, none of them is used routinely because of the low evaluability or the time consuming nature. We developed a new practical method which is simple, rapid, and applicable to fresh human tumors. The principle of the method is to measure the ATP content of cancer cells by bioluminescence after drug exposure. A linear relationship was observed between either the number of cells or their viability and light intensity. Four established human stomach cancer cell lines and five colon cancer cell lines were examined for their chemosensitivity with a test plate having 96 wells. A clear dose-dependent response was seen with almost all drugs tested in this study, and each cell line showed an identical response to drugs. For the clinical application, cancer cells taken from three human solid tumors were tested. In all cases, the chemosensitivity was clearly evaluable. This simple, rapid and sensitive method can be a good indicator for the determination of anticancer agents in cancer chemotherapy.

[Human epidermal growth factor (h-EGF) in gastric carcinomas]

Two hundred and twenty one gastric carcinomas were immunohistochemically stained for h-EGF and we examined the correlation between h-EGF immunoreactivities and histologic findings. Regarding macroscopic and histologic types, incidence of h-EGF immunoreactivities in infiltrating type and in poorly differentiated type was significantly higher than those in localized type and in differentiated type, respectively. In addition, h-EGF producing carcinomas showed high positive rate in prognostic serosal involvement and scirrhous type in stroma. Prognosis in patients with h-EGF producing tumors was poorer than that in those with h-EGF non-producing tumors, especially in stages II and III. These results suggest that h-EGF immunoreactivities serves as a biological marker of high malignancy.

Plasminogen activators and plasminogen activator inhibitor in malignant and non-malignant ascitic fluid

Ascitic fluid from tumour patients (hepatoma, gastric cancer, gallbladder cancer, colorectal cancer, ovarian cancer) and from non-malignant diseases (liver cirrhosis, congestive heart failure) were compared with respect to their content of determinants of the fibrinolytic system, tissue-type plasminogen activator antigen (t-PAag) and activity (t-PAact), urokinase-type plasminogen activator antigen (u-PA) and plasminogen activator inhibitor activity (PAI). Furthermore, SDS-polyacrylamide slab-gel electrophoresis (SDS-PAGE) was performed to evaluate molecular weight distribution of the detectable fibrinolytic parameters. In malignant ascites, PAI activity was three to four times higher, and increased complex formation of PAI with t-PA could be demonstrated, compared with non-malignant ascitic fluid. Tissue-type plasminogen activator antigen and activity showed a similar concentration in ascites of both study groups. Urokinase-type plasminogen activator antigen was detectable neither in ascites of malignant nor in ascites of non-malignant origin. It is concluded that t-PA is the physiological plasminogen activator in ascites and that increased PAI levels followed by increased complex formation between t-PA and PAI might reflect a reaction of the peritoneum.

[Biochemical study on interstitial proteins of human gastric cancer tissue with special reference to cross-linking amino acids of collagen and elastin]

The present study was undertaken to examine malignant alterations of collagen and elastin in human stomach cancer. Results of the study are as follows: 1. Content of hydroxyproline which in characteristic amino acid in collagen was elevated in stomach cancer tissues of Bormann types I to IV as compared to that of the uninvolved stomach. 2. When hydroxyproline content in stomach cancer of type IV (scirrhous) was compared to that in other types (I to III) of the cancer, the content in scirrhous was significantly elevated compared with that in cancers of other types, in terms of dry weight of whole tissue, number of cancer cells, and of insoluble proteins which are rich in collagen and elastin. However, when hydroxyproline was determined on two histological layers (mucosa plus submucosa layer and muscular plus serosa layer) separated from the involved and uninvolved stomach tissues, no significant difference in hydroxyproline content was observed between the scirrhous and non-scirrhous cancers. These observations may imply that an increased collagen synthesis in the scirrhous occurs in many layers of stomach tissue but is not restricted in a particular layer. 3. Non-reducing cross-link amino acids of collagen, pyridinoline and histidinoalanine, were assayed on the involved and uninvolved tissues. Pyridinoline content was higher in stomach cancers of Bormann types I to IV, while no significant difference of histidinoalanine content was found. These observations suggest that there is an increased cross-linking of collagen in stomach cancer. 4. Elastin concentration in stomach cancer was determined through the assay of desmosine and isodesmosine which are specific cross-link amino acids in elastin. The contents of these amino acids was increased in stomach cancer tissues of types I to IV as compared with that in the uninvolved tissue. 5. A ratio of desmosine plus isodesmosine to hydroxyproline was higher in the involved stomach than was in the uninvolved, suggesting that increased elastinosis exceeds collagenosis in stomach cancer.

Secretion of plasminogen activators by human colorectal and gastric tumor explants

Conditioned media from explants of human colorectal and gastric tumors in short-term organ culture were analysed for plasminogen activator activity, activity toward the synthetic urokinase substrate, Spectrozyme-UK, and for the presence of urokinase antigen using monospecific goat antibody, by enzyme-linked immunosorbent assay. Comparisons were made between primary tumors, adjacent normal mucosa and metastatic lesions. These analyses were carried out on unfractionated culture fluids and on fractions obtained by fast protein liquid chromatography separation using Superose 6 gels. Plasminogen activator activity, tested by azocaseinolysis in the presence of added plasminogen, was restricted to peaks of 55 kD and 155 kD. These were of the urokinase type as shown by specific immunoinhibition and by absorption by an antiurokinase antibody-Affigel 10 column. Spectrozyme-UK, in addition to these peaks, detected a series of higher molecular weight activities, the largest of which appeared in the void volume, and were therefore of greater than 10(6) molecular weight. These activities were greatly increased by inclusion of trace plasmin indicating that these components were mostly in their proenzyme forms. The characteristics of these very large enzymes were similar to those isolated earlier from a human lung cancer cell line. Comparison of the primary and metastatic tumors confirmed earlier observations showing that urokinase secretion by the metastatic tumors was greatly reduced in comparison with the primary tumors: in the colon carcinomas it was 10 per cent of the value for the primary, in the gastric tumors 3 per cent, whether means or medians were compared (P less than 0.0001). This large difference was characteristic only of plasminogen activator secretion assayable by azocaseinolysis; activities toward Spectrozyme-UK, and antigen reacting with anti-urokinase antibody, were considerably less different in the two groups. In individual tissues, no correlation was found between the amount of extractable plasminogen activator and amounts secreted, or between the latter and the amount of lactic acid released. It is postulated that the greatly reduced plasminogen activator secretion by explants of metastatic tumors may be a phenotypic characteristic of distinct advantage for cancer cells destined to initiate metastatic foci, and may contribute to the ability of circulating cancer cells to lodge in the blood vessels of the target organ.

Epidermal growth factor receptors in cancer tissues of esophagus, lung, pancreas, colorectum, breast and stomach

The levels of epidermal growth factor (EGF) receptors were investigated in surgically resected tumors of various origins including esophagus (n = 33), lung (n = 14), pancreas (n = 9), colorectum (n = 10), breast (n = 23) and stomach (n = 8). The 125I-EGF binding capacities of squamous cell carcinomas of esophagus and lung were exceptionally higher than those of the other cancer tissues. Immunohistochemical staining with an anti-EGF receptor monoclonal antibody detected EGF receptors in the basal cells and parabasal cells of normal esophageal epithelium and in all the cancer cells of squamous cell carcinoma tissues of esophagus and lung. DNA replicating cells were examined by the bromodeoxyuridine staining method and it was found that the basal cells and parabasal cells of normal epithelium and peripheral cells of cancer pearls are proliferating. Contrary to this, a tumor antigen TA-4, known as a specific marker for squamous carcinoma, was detected in the differentiated cancer cells and in middle-layer squamous cells. These results strongly suggest that the increase in EGF receptor levels may be associated with the development of human squamous cell cancers of esophagus and lung. Thus, measurement of EGF receptor expression in tumor tissues has diagnostic value and should prove useful for the development of new therapies.

Correlation of DNA ploidy and proliferative activity in human gastric cancer

Analysis of DNA ploidy patterns was performed on 129 cases of primary gastric cancer and the results were correlated with histologic findings and in vivo bromodeoxyuridine (BrdU) labeling. Forty-nine cases were diploid (38%) and 80 cases were aneuploid (62%). There was no correlation between DNA ploidy and histologic type. In aneuploid tumors, incidence of lymphatic invasion, lymph node metastasis, and rate of advanced cases were significantly higher than those in diploid tumors. During the follow-up period of 5 to 10 years, 23 of 40 patients (55%) with aneuploid tumors died of disease within 3 to 120 months. Only 13 of 36 patients (36%) with diploid tumors died of disease. The BrdU labeling indices (BrdU LI) ranged from 2.8% to 26.7%, with a mean of 10.4%. There was no correlation between BrdU LI and histologic type or stage. The mean BrdU LI of early cancers was 8.1%. The mean BrdU LI of advanced cancers was 11.9%. The BrdU LI of cancers with lymphatic invasion or lymph node metastasis was higher than those without them. The mean BrdU LI of diploid cancers was 6.0%. The mean BrdU LI of aneuploid cancers was 11.9%. There was a good correlation between BrdU LI and DNA ploidy patterns. These results indicate that DNA ploidy patterns and BrdU LI may possibly be useful prognostic markers for gastric cancers.

The possibility of nonpolypoid carcinogenesis in the large intestine as inferred from frequencies of DNA aneuploidy of polypoid and crater-shaped carcinomas

DNA ploidy patterns were studied by cytofluorometry in 60 cases of crater-shaped invasive carcinoma and 30 cases of polypoid tumor (severe dysplasia or submucosally invasive carcinoma located in the pedunculated, semipedunculated, or sessile polyp) of the large intestine. The data were compared with 20 cases of intramucosal differentiated (or intestinal type) adenocarcinoma of the stomach, with special reference to their macroscopic shape and frequency of DNA aneuploidy. DNA aneuploidy was found in 77% of the crater-shaped carcinomas and in 17% of the polypoid tumors of the large intestine. The frequencies were significantly different and the frequency gap amounted to 60%. However, 18 of 20 (90%) gastric adenocarcinomas were nonpolypoid in shape, whereas two (10%) were polypoid. DNA aneuploidy was found in 50% of the gastric adenocarcinomas and 56% of the nonpolypoid gastric adenocarcinomas. This value did not differ from the values reported previously for the submucosally invasive and advanced crater-shaped intestinal type adenocarcinomas of the stomach. Biologic characteristics of adenocarcinomas of the large intestine can be compared with those of intestinal type adenocarcinomas of the stomach, because intestinal type gastric adenocarcinoma is surrounded mostly by intestinalized mucosa and considered to arise from the epithelium under induction or progression of intestinal differentiation. Therefore, we inferred that the frequency gap in DNA aneuploidy between the crater-shaped and polypoid tumors of the large intestine implies that in the large intestine approximately 60% of the crater-shaped invasive carcinomas develop from the small nonpolypoid carcinomas.

Gastric carcinoma metastatic to the breast diagnosed by mucosubstance histochemistry and electron microscopy

Bilateral breast tumors with a histologically scirrhous pattern were conclusively diagnosed as gastric carcinoma metastatic to the breast using mucosubstance histochemistry and electron microscopy. The majority of the carcinoma cells gave histochemically positive reactions for galactose oxidase-Schiff, stable class III con A, and high-iron diamine-alcian blue (HID-AB). Also electron microscopically, numerous HID-positive mucus droplets (sulfomucin) were seen in the carcinoma cells. These findings invalidated the possibility that the carcinomas were primary breast cancer. The practical applications of distinctive patterns of mucus secretion are discussed.

[Correlation of epidermal growth factor receptor status and clinical outcome in gastric carcinoma]

Analysis of epidermal growth factor receptor (EGFR) was performed on 242 primary gastric carcinomas and the results correlated with histologic findings and S-phase fractions measured by bromodeoxyuridine (BrdU) labeling. They were stained for EGFR by means of an indirect immunoperoxidase technique using a monoclonal antibody against the receptor. Seventy-six of these cancer tissues exhibited EGFR reactivities. All the cancer cell membranes were stained and sometimes the stroma were stained. These EGFR status were then compared on the basis of pathologic findings including macroscopic type, depth of invasion, differentiation type, vascular invasion and lymph node metastasis. Staining for EGFR in Borrmann's 3 or 4 type was significantly stronger than those in other macroscopic types. The staining for EGFR was closely related to the poorly differentiated type and frequent serosal involvement. BrdU labeling index was studied in 25 cases. These values were from 2.3% to 18.6%, with a mean of 10.4%. The mean BrdU labeling index of EGFR positive cases was 12.2%, of negative cases 7.6%, respectively. There was a good correlation between BrdU labeling index and EGFR status. In addition, There was a signifiCANT 8P less than 0.05) correlation between the presence of the EGFR and poor prognosis. However, EGFR status was not significantly correlated with the lymph node metastasis, vessel invasion and size of the tumors. These results indicate that demonstration of EGFR status may be useful in prognosis and this receptor may be a suitable target for therapy.

Procoagulant activity of gastric, colorectal, and renal cancer is factor VII-dependent

The PA of GC, CC, and RC extracts was assayed by the recalcification of human normal or F VII-DP, and the PA of normal tissue was also determined. The PA of normal tissue was higher than that of the cancer tissues in all groups of specimens. Substitution of normal plasma by F VII-DP resulted in significant depression of the PA and the differences in the PA between the normal and cancer tissue samples disappeared. Preincubation of normal and cancer tissue extracts with the cysteine proteinase inhibitors, mercuric chloride and iodoacetamide, did not affect the PA of these extracts. We conclude that the PA of the investigated cancer extracts is factor VII-dependent and can be related to the presence of tissue factor within cancer tissue.

[Estrogen receptors in human gastric, hepatocellular, and gallbladder carcinomas and normal liver tissues]

Steroid binding assay using the dextran coated charcoal (DCC) method was applied to human tissues including tumors of the digestive organs, and the results were compared with those of enzymeimmunoassay (EIA) and immunocytochemical assay (ICA) with monoclonal antibody against human estrogen receptor of MCF-7 breast cancer cells. Using the DCC method, estrogen receptor activity was detected in 6 of 26 cases (23.1%) with gastric carcinoma, 3 of 16 hepatocellular carcinoma cases (18.8%), 1 of 3 gallbladder carcinoma cases (33.3%), and both of the 2 cases (100%) with normal liver tissue. However, using EIA, no ER activity was detected in any case. Moreover, ER positive cells were not found by immunohistochemical staining in the gastric carcinoma cases or in normal liver tissue, both of which showed ER activity by the DCC method. These results suggest that the estrogen receptor like material exists in cytosol of the human digestive tumors and normal liver tissue, but that the specificity of the antibodies against estrogen receptor molecules in these tumors may be different from that of the breast tumors.

[Study on neuro-endocrine type of gastric carcinoma]

One hundred patients with gastric carcinoma resected surgically were studied by PAP immunoperoxidase and ultrastructural method. It was found that the tumor cells were positive for gastrin, serotonin, somatostatin as well as argyrophil particles in 19 patients. In these 19 patients, the quantity of endocrine tumor cells surpassed half of its total cancer cells in 4, leading to a separate entity of neuroendocrine gastric carcinoma. The authors hope to introduce this new subtype into the classification of gastric carcinoma. Among the 100 cases, 50 patients with undifferentiated carcinomas contained the NE cells in 16 (32%), the remains for high differentiated adenocarcinomas had the NE cells in 3 (6%) only. It was suggested that the appearance of NE tumor cells was closely correlated to differentiation of gastric carcinoma. This study theoretically demonstrated the heterogenicity of gastric carcinoma and supported the theory that different kinds of tumor cells (endocrine and nonendocrine) may have a common origin and are derived from the endoembryogenetic immature precursor cells.