Gains, losses, and amplifications of genomic materials in primary gastric cancers analyzed by comparative genomic hybridization

By means of comparative genomic hybridization (CGH), we screened 58 primary gastric cancers for changes in copy number of DNA sequences. We detected frequent losses on Ip32-33 (21%), 3p21-23 (22%), 5q14-22 (36%), 6q16 (26%), 9p21-24 (22%), 16q (21%), 17p13 (48%), 18q11-21(33%), and 19(40%). Gains were most often noted at I p36 (22%), 8p22-23 (24%), 8q23-24 (29%), 11q12-13 (24%), 16p(21%), 20p (38%), 20q (45%), Xp21-22(38%), and Xq21-23 (43%), with high-level amplifications at 6p21(2%),7q31(10%), 8p22-23(5%), 8q23-24 (7%), 11q13(4%), 12p12-13(4%), 17q21(2%), 19q12-13(2%), and 20q13(2%). High-level amplification at 8p22-23 has never been reported in any other cancer type and its frequency was as high as that reported for the MYC, MET, and KRAS genes. We narrowed down the smallest common amplicon to 8p23.1 by reverse-painting FISH to prophase chromosomes. Southern blot analysis using one EST marker (D38736) clearly demonstrated that amplification of this exon-like sequence had occurred in all three tumors in which amplifications at 8p22-23 had been detected by CGH. Our data provide evidence for several, previously undescribed, genomic aberrations that are characteristic of gastric cancers.

Gains, losses, and amplifications of genomic materials in primary gastric cancers analyzed by comparative genomic hybridization

By means of comparative genomic hybridization (CGH), we screened 58 primary gastric cancers for changes in copy number of DNA sequences. We detected frequent losses on Ip32-33 (21%), 3p21-23 (22%), 5q14-22 (36%), 6q16 (26%), 9p21-24 (22%), 16q (21%), 17p13 (48%), 18q11-21(33%), and 19(40%). Gains were most often noted at I p36 (22%), 8p22-23 (24%), 8q23-24 (29%), 11q12-13 (24%), 16p(21%), 20p (38%), 20q (45%), Xp21-22(38%), and Xq21-23 (43%), with high-level amplifications at 6p21(2%),7q31(10%), 8p22-23(5%), 8q23-24 (7%), 11q13(4%), 12p12-13(4%), 17q21(2%), 19q12-13(2%), and 20q13(2%). High-level amplification at 8p22-23 has never been reported in any other cancer type and its frequency was as high as that reported for the MYC, MET, and KRAS genes. We narrowed down the smallest common amplicon to 8p23.1 by reverse-painting FISH to prophase chromosomes. Southern blot analysis using one EST marker (D38736) clearly demonstrated that amplification of this exon-like sequence had occurred in all three tumors in which amplifications at 8p22-23 had been detected by CGH. Our data provide evidence for several, previously undescribed, genomic aberrations that are characteristic of gastric cancers.

Marriage of a medium-term liver model to surrogate markers--a practical approach for risk and benefit assessment

The need for a reliable medium-term alternative to traditional long-term rodent test protocols for carcinogen risk assessment is pressing given the immense variety of compounds being developed for introduction into the human environment. The established lack of a complete correlation between mutagenicity and carcinogenicity means that recourse must be made to an in vivo model. Optimally, this model should be able to detect not only complete carcinogenic or promoting potential but also any ability to inhibit neoplasia. In order to be effective, it must take into account the available detailed knowledge on mechanisms of action of carcinogens and modulating agents. The Ito model, for which a uniquely comprehensive set of background data has already been accumulated, has a solid scientific basis; this model utilizes quantitative data for glutathione S transferase-positive foci as the preneoplasia-based surrogate end point (PSE). A very practical candidate for routine application, its predictive power, its flexibility, and its capacity to incorporate a range of mechanism-based surrogate end points (MSEs) provide a powerful tool for attainment of the twin goals of detecting carcinogenic agents and identifying promising chemopreventors.

Endoscopic incision and balloon dilatation for cicatricial anastomotic strictures

BACKGROUND/AIMS

Endoscopic incision or balloon dilatation is common therapy for cicatricial anastomotic strictures after gastrointestinal surgery. These therapies are not always effective.

METHODOLOGY

There were 6 patients who failed either endoscopic incision or balloon dilatation alone and who underwent a combination of the two therapies. Two or three small radial incisions were made in the scar of the stricture with the endoscopic electrocautery under direct vision with fiberscopy. Then, the incisions were split bluntly and the stenosis was dilated over 15-20 minutes with balloon-dilator. This procedure was performed once or twice at a 2-week interval.

RESULTS

In 5 of the 6 patients, the stenosis was improved in subjective criteria and objective symptoms. In the last patient, only objective improvement was noted. There were no complications.

CONCLUSIONS

Endoscopic incision plus balloon dilatation is an effective and safe treatment for cicatricial anastomotic strictures which have failed either therapy alone.

[Treatment of postoperative recurrence of digestive cancers: peritonitis carcinomatosa]

Carcinomatous peritonitis is the most frequent type of recurrence observed after surgery for cancer of the digestive tract. Most patients with carcinomatous peritonitis present with bowel obstruction and/or ascites. Surgical treatment including colostomy and intestinal anastomosis and chemotherapy have been attempted in patients with carcinomatous peritonitis, although the results have not been satisfactory. New drug delivery systems, such as mitomycin C-adsorbed charcoal, anticancer drugs entrapped in microspheres, and immunoconjugates composed of anticancer drugs and antibodies, will be powerful new tools for the treatment of metastatic cancer.

Enterovirus 71 from fatal and nonfatal cases of hand, foot and mouth disease epidemics in Malaysia, Japan and Taiwan in 1997-1998

Enterovirus 71 (EV71), one of the major causative agents for hand, foot and mouth disease (HFMD), is sometimes associated with severe central nervous system diseases. In 1997, in Malaysia and Japan, and in 1998 in Taiwan, there were HFMD epidemics involving sudden deaths among young children, and EV71 was isolated from the HFMD patients, including the fatal cases. The nucleotide sequences of each EV71 isolate were determined and compared by phylogenetical analysis. EV71 strains from previously reported epidemics belonged to genotype A-1, while those from recent epidemics could be divided into two genotypes, A-2 and B. In Malaysia, genotype A-2 was more prevalent, while in Japan and Taiwan, B genotype was more prevalent. Two isolates from fatal cases in Malaysia and one isolate from a fatal case in Japan were genotype A-2. However, all isolates from three fatal cases in Taiwan belonged to genotype B. The severity of the HFMD did not link directly to certain genotypes of EV71.

Number and anatomical extent of lymph node metastases in gastric cancer: analysis using intra-lymph node injection of activated carbon particles (CH40)

BACKGROUND

The long-term survival of 200 patients with gastric cancer who underwent radical gastrectomy was analyzed with respect to the number and anatomical extent of lymph node metastasis. All of the patients received intra-lymph node injection of fine activated carbon particle solution (CH40) during surgery.

METHODS

The average number of resected lymph nodes increased in line with the anatomical level of lymph node dissection; 32.5 per patient in D1, 42.3 in D2, 3 and 66.3 in D4. The percentage of blackened lymph nodes without metastasis (42.4%) was slightly higher than that of lymph nodes containing metastasis (37.2%), but the difference was not statistically significant. Of the 200 patients, 61 (30.5%) had microscopic evidence of metastatic lymph node involvement. Twenty-two patients had between one and three metastatic lymph nodes, 19 had between four and nine and 20 patients had more than nine. The 5-year survival rate was 93.1% in patients without lymph node metastasis, 71.9% in patients with 1-8 metastatic nodes, 36.1% in patients with 4-9 nodes and 19.2% in patients with > 9 nodes.

RESULTS

The 5-year survival rate according to the anatomical extent of metastatic lymph nodes was 93.1% in n0, 63.1% in n1, 37.9% in n2, 27.8% in n3 and 0% in n4. The number of metastatic lymph nodes and also their anatomical extent were identified as independent prognostic factors for survival by multivariate analysis.

CONCLUSION

The number and anatomical extent of metastatic lymph nodes have similar impacts on prognosis in gastric cancer.

No survival benefit from combined pancreaticosplenectomy and total gastrectomy for gastric cancer

BACKGROUND

It remains unknown whether extended surgery improves the survival rate of patients with gastric cancer. This study was a review of combined pancreaticosplenectomy with total gastrectomy for gastric cancer.

METHODS

The clinicopathological details of 190 patients who underwent combined pancreaticosplenectomy with total gastrectomy between 1969 and 1996 were compared retrospectively with those of 206 patients who underwent total gastrectomy with splenectomy alone.

RESULTS

There was no statistical difference in the survival rate when pancreaticosplenectomy was added to total gastrectomy. The mortality rate was similar, but the morbidity rate was higher in patients who had pancreaticosplenectomy. Six patients who had direct pancreatic invasion and two thought to have involved lymph nodes along the splenic artery survived for more than 5 years after operation. In the latter group, the metastatic lymph nodes along the splenic artery could have been resected without pancreatectomy.

CONCLUSION

Since a combined pancreaticosplenectomy adds no survival advantage to total gastrectomy for gastric cancer, this procedure should no longer be regarded as routine.

[Angiographic diagnosis and management of bleeding from the digestive organs]

Gastrointestinal bleeding is recently seen less often by the angiographer. This is mainly due to advances in endoscopy, and nuclear medicine. When patients with gastrointestinal bleeding are referred, endoscopic diagnosis and therapy should be performed at first. However, when it is impossible to diagnose or to control the bleeding, angiography must be considered as soon as possible. Intra-abdominal bleeding should be diagnosed by angiography at first. In both cases, embolization is generally safe and effective depending on the advance of occlusive agents.

Complete omentectomy and extensive lymphadenectomy with gastrectomy improves the survival of gastric cancer patients with metastases in the adjacent peritoneum

BACKGROUND/AIMS

The omentum is the site where peritoneal metastases occur most frequently. It has not been shown whether complete resection of the omenta during gastrectomy improves the survival of gastric cancer patients with macroscopic peritoneal metastases.

METHODOLOGY

We retrospectively analyzed 126 patients who underwent gastrectomies for gastric cancer with peritoneal metastases but without hematogenous metastases. The 126 patients were stratified according to their grade of peritoneal metastases into three groups: the P1 patients (patients with peritoneal metastases in the adjacent peritoneum but not in the distant peritoneum); the P2 patients (patients with a few peritoneal metastases in the distant peritoneum); and the P3 patients (patients with many metastases in the distant peritoneum). In each group, the survival and clinicopathological characteristics were compared between patients treated by complete resection of the greater omentum and the lesser omentum plus extensive lymphadenectomy during gastrectomy, versus patients treated by incomplete resection of the omenta and non-extensive lymphadenectomy during gastrectomy.

RESULTS

Complete omentectomy and extensive lymphadenectomy during gastrectomy improved survival significantly only in the P1 patients. Other clinicopathological characteristics did not differ between them.

CONCLUSION

Complete omentectomy and extensive lymphadenectomy is recommended in patients with peritoneal metastases in the adjacent peritoneum but not in the distant peritoneum.

Presence of a threshold for promoting effects of phenobarbital on diethylnitrosamine-induced hepatic foci in the rat

The dose dependence of the hepatopromoting effects of phenobarbital (PB) was investigated in a rat liver medium-term bioassay (Ito test) to elucidate a practical threshold level. F344 rats were given a single i.p. injection of diethylnitrosamine (200 mg/kg body wt) and subjected to two-thirds partial hepatectomy at week 3. Commencing 2 weeks from the start, PB at doses of 0, 1, 2, 4, 7.5, 15 or 500 p.p.m. in experiment 1 and 0, 0.01, 0.1 or 0.5 p.p.m. in experiment 2 were fed to the rats for 6 weeks. Experiment 3 was conducted to confirm previous data using the same medium-term bioassay, with PB at doses of 0, 1, 2, 4, 7.5, 15, 30, 60, 125, 250 or 500 p.p.m. fed to the rats. All surviving animals were killed at week 8 in these experiments and their livers were immunohistochemically examined for expression of glutathione S-transferase placental form (GST-P). Quantitative values for GST-P-positive foci in the liver were increased dose dependently in rats given 60-500 p.p.m. PB. However, those for doses in the range 1-7.5 p.p.m. demonstrated a decrease as compared with the control group (0 p.p.m.), with significant differences observed for 1 and 2 p.p.m.. The results for 15-30 and 0.01-0.5 p.p.m. were comparable with the control values. Examination of transforming growth factor-alpha (TGF-alpha)-positive foci also produced similar results to those for GST-P in experiment 1. Immunohistochemical staining of TGF-alpha and GST-P using serial liver sections demonstrated that the TGF-alpha-positive foci comprised a sub-population of the GST-P-positive lesions, being approximately 1/8-1/10th as common in livers of animals treated with PB. TGF-alpha-positive foci were almost always negative on immunostaining for TGF-beta. Western blotting for proteins CYP2B1, 2C6 and 3A2 revealed a good correlation between changes in GST-P-positive foci and CYP3A2 protein expression. The finding of inhibition effects at low doses of PB confirms the presence of a threshold level for promoting effects by PB on liver carcinogenesis in rats.

Medium-term bioassays as alternative carcinogenicity test

A medium-term liver bioassay system for rapid detection of carcinogenic agents using male F344 rats has been developed, in order to bridge the gap between long-term carcinogenicity tests and short-term screening assays. The system is fundamentally based on the two-stage hypothesis of carcinogenesis: initiation with diethylnitrosamine (200 mg/kg bw, i.p.) is followed by test chemical administration during the second, in combination with 2/3 partial hepatectomy. It requires only 8 weeks for animal experimental treatment and a further few weeks for quantitative analysis of immunohistochemically-demonstrated glutathione S-transferase placental form positive hepatic foci. A total of 291 chemicals/substances have already been analyzed in this laboratory and the efficacy of the system for hepatocarcinogens has thereby been well established. This bioassay is particularly useful for dose-response and chemical mixture studies, usually requiring large-scale experiments and also for evaluation of chemopreventive agents. Another bioassay, a medium-term multiorgan bioassay system, using 5 different chemical carcinogens, diethylnitrosamine (DEN), N-methylnitrosourea (MNU), N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN), 1,2-dimethylhydrazine (DMH) and 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN), has also been established for rapid detection of not only hepatocarcinogens, but also other organ-target carcinogens. Rats were initially treated with a single i.p. administration of 100 mg/kg DEN, 4 i.p. administrations of 20 mg/kg MNU, 4 s.c. doses of 40 mg/kg DMH for 2 weeks and then 0.1% DHPN for 2 weeks. Test chemicals are administered after the carcinogens exposure. Animals were sacrificed at the end of week 36, and major organs were examined histologically. Carcinogenic activities of test chemicals were compared between the test chemical treated group and carcinogen exposures group (control group). It is increasingly becoming regarded that these bioassays are useful methods and are appropriate alternative tests systems for carcinogenicity risk assessment. Therefore, 'the International Conference on Harmonization (ICH) of Technical Requirements for the Registration of Pharmaceuticals for Human Use' has proposed that these two bioassays can be used as "additional tests for carcinogenic activity in vivo."

Selectivity of sphingosine-induced apoptosis. Lack of activity of DL-erythyro-dihydrosphingosine

Sphingosine (Sph) is emerging as an intracellular regulator of cellular differentiation and apoptosis (Ohta, et al., Cancer Res., 55, 691-697, 1995). We have recently found that both Sph and its methylated derivative N,N-dimethylsphingosine (DMS) inhibit mitogen-activated protein kinase (MAPK) activity, suggesting that Sph-induced apoptosis may be mediated at least partly through inhibition of MAPK (Sakakura, et al., Int J Oncol, 11, 31-39, 1997). We report in this study that three stereoisomers, D-erythro-Sph, L-threo-Sph, and DL-erythro-dihydrosphingosine, were tested in induction of apoptosis and inhibition of MAPK activity in three different kinds of solid tumor cell lines. D-erythro-Sph was strongest in these effects among three compounds. L-threo-Sphingosine was partly active. On the other hand, DL-erythro-dihydrosphingosine was totally inactive. These results demonstrate the specificity of sphingosine action in induction of apoptosis and inhibition of MAPK, suggesting that Sph may play an important role as a physiological intracellular messenger of apoptosis in these cancer cells.

Recent advances in surgical treatment have improved the survival of patients with gastric carcinoma

BACKGROUND

Mortality resulting from gastric carcinoma is decreasing. This is mainly due to vigorous endoscopic screening and the consequent higher incidence of early detection of the disease. In this study, to evaluate the effect of surgical treatment on the prognoses of patients with gastric carcinoma, the survival of 1579 patients who underwent gastrectomy between 1970 and 1994 was retrospectively analyzed.

METHODS

The patients were divided into 5 groups at 5-year intervals. Postoperative survival was compared among the groups.

RESULTS

Postoperative survival was significantly improved in the later groups for patients with Stage I, II, III, and IV disease. A multivariate analysis of prognostic factors revealed that the time period during which the gastrectomy was performed was an independent predictor of survival.

CONCLUSIONS

It was concluded that survival has been improved by recent advances in the surgical approach to gastric carcinoma.

A pilot study of fiberscopy-guided local injection of anti-cancer drugs bound to carbon particles for control of rectal cancer

Rectal cancer patients with contra-indicatory risks may not be able to undergo surgery. In these cases the preferred treatment is chemotherapy. The present dosage formulation, consisting of an anti-cancer drug bound to activated carbon particles, was designed to deliver the anti-cancer drug at high concentration selectively to the injection site as well as to the regional lymph nodes and to improve survival of mice bearing cancer with nodal metastases, as compared to the same dose of aqueous anti-cancer drug in animal experiments. The present clinical trial includes two patients with histologically confirmed adenocarcinoma of the rectum and who had risks contra-indicating surgery. Carbon particles adsorbing anti-cancer drugs totaling 400 mg of methotrexate and 32 mg of mitomycin C in one patient and 100 mg of methotrexate and 8 mg of mitomycin C in another patient were injected into the cancer tissue under guidance of a colono-fiberscope. The rectal cancers were successfully reduced in size and controlled over 2 years or 6 months until the patients died from other causes. Side effect was mild. Local injection of this dosage formulation will be useful for the control of rectal cancer in patients who cannot undergo surgery.

Variation in susceptibility to the induction of forestomach tumours by butylated hydroxyanisole among rats of different strains

The forestomach carcinogenicity of butylated hydroxyanisole (BHA) was compared in males of the F344, SHR, Lewis and Sprague Dawley rat strains. Groups of 30 6-wk-old animals were given a pellet diet containing 2% BHA for 104 wk. Forestomach squamous cell papillomas and hyperplasias developed in all rats given BHA, independent of the strain, but the incidences of squamous cell carcinomas (SCCs) differed considerably: F344, 26.7% (8/30) SHR, 76.7% (23/30) SD, 36.7% (1130) Lewis, 6.7% (2/30). Cytotoxic effects, reflected by inflammation, were also most severe in the SHR strain, correlating well with the development of SCCs. The present results indicate that major strain differences exist regarding BHA rat forestomach carcinogenesis and that sensitivity to cytotoxicity might be an important parameter.

Therapeutic effects of 5-fluorouracil microspheres on peritoneal carcinomatosis induced by Colon 26 or B-16 melanoma in mice

The delivery formulation 5-FU-MS [5-fluorouracil (5-FU) incorporated in microspheres composed of a poly(glycolide-co-lactide) matrix] slowly releases 5-FU over 3 weeks. 5-FU-MS delivers higher concentrations of the drug to the i.p. tissues for a longer period of time with lower blood plasma concentrations than does an aqueous 5-FU solution and reduces toxicity. In this study, we evaluated the therapeutic effects of 5-FU-MS on peritoneal carcinomatosis in mice. Four days after an i.p. inoculation with Colon 26 or B-16 PC melanoma, 5-FU at 200 mg/kg was administered i.p. as 5-FU-MS or as an aqueous solution of 5-FU. 5-FU-MS extended the survival of mice bearing Colon 26 or B-16 PC melanoma significantly better than the equivalent dose of aqueous 5-FU solution.

Ca2+-induced distance change between points on actin and troponin in skeletal muscle thin filaments estimated by fluorescence energy transfer spectroscopy

Fluorescence resonance energy transfer spectroscopy has been used to study the spatial relationships between probes attached to actin and troponin in the reconstituted skeletal muscle thin filament in the presence and absence of Ca2+ ions. Gln-41 and the nucleotide-binding site of actin were selectively labeled with the acceptor probe: fluorescein cadaverine and 2'(or 3')-O-(2,4,6-trinitrophenyl)adenosine 5'-diphosphate (TNP-ADP), respectively. Troponin was selectively labeled at positions 9 or 133 of troponin-I and 98 of troponin-C with a donor probe; 5-(2-iodoacetylaminoethyl)aminonaphthalene 1-sulfonic acid (IAEDANS). The distances between probes attached to position 133 of TnI and Gln-41 or the nucleotide site of actin were determined to be 51.6+/-1.2 and 42.7+/-0.9 A respectively in the presence of Ca2+, and these distances decreased by 11.5 and 9.3 A respectively in the absence of Ca2+ ions. The distances between the probes attached to position 9 of TnI and Gln-41 or the nucleotide site of actin were determined to be 59.1+/-2.0 or 49.3+/-1.5 A respectively in the presence of Ca2+, and the distances decreased by 5.3 or 3.7 A in the absence of Ca2+. The distances between probes attached to position 98 of TnC and Gln-41 or the nucleotide site of actin were determined to be 55.1+/-1.7 and 57+/-5 A in the presence of Ca2+ and the distances increased slightly by approximately 1 A in the absence of Ca2+. The results suggest that the C-terminal domain of troponin I moves to the outer domain of actin during inhibition, while the C-terminal domain of TnC does not move much.

Analysis of histological therapeutic effect, apoptosis rate and p53 status after combined treatment with radiation, hyperthermia and 5-fluorouracil suppositories for advanced rectal cancers

The tumour-suppressor gene p53 encodes a transcription factor that plays a critical role in the induction of G1 cell cycle arrest and apoptosis after DNA damage. To clarify the role of the p53 gene and apoptosis in combined hyperthermia, chemotherapy and radiation (hyperthermochemoradiotherapy, HCR therapy) for rectal cancer, we examined the histological response, rate of apoptosis, DNA fragmentation and p53 status in tumours from 28 patients undergoing HCR therapy before surgery and from 22 patients who did not have preoperative treatment. The therapeutic effect of HCR therapy was closely correlated with the rate of apoptosis; the correlation was statistically significant, suggesting that this effect occurs through apoptosis. The incidence of p53 mutations in the treated group were as follows: in tumours resistant to HCR therapy, four of seven (57.1%); intermediately sensitive, 7 of 13 (53.9%); or sensitive, three of eight (37.5%), suggesting that the therapeutic effect and apoptosis rate were related to the p53 status of the tumours to some extent, but the relation was not statistically significant. In the 22 control tumours (non-treated group), the apoptosis rate was 2.0 +/- 1.1%, and there was no significant difference in p53 status compared with the HCR group. Our study indicates that the pathological response to HCR therapy correlates with the rate of apoptosis with statistical significance and that it induces the therapeutic effect more significantly in rectal cancer cells with wild-type p53, although HCR therapy-induced apoptosis also occurs in some rectal cancers with mutated p53. Therefore, this combination therapy can induce an additive or synergistic anti-tumour effect in rectal cancers with wild-type p53 as well as in those with mutated p53 through apoptosis, offering new therapeutic opportunities and a better prognosis.

Hyperechoic appearance of hepatic parenchyma on ultrasound examination of patients with blunt hepatic injury

OBJECTIVE

To study the significance of a geographic hyperechoic liver parenchyma pattern on ultrasound (US) examination of patients with blunt abdominal injury.

DESIGN

Prospective clinical study with double-blind evaluation of images and clinical data.

METHODS AND MAIN RESULTS

We performed US examinations in 831 consecutive patients admitted to our hospital for blunt abdominal trauma and identified 33 with a geographic hyperechoic pattern in the liver. We correlated the appearance with computed tomographic images and with clinical, angiographic, and scintigraphic data. All patients with a geographic hyperechoic pattern showed mild computed tomographic evidence of hepatic injury (Mirvis grade 2, 69%; Mirvis grade 3, 31%). Excluding patients who required urgent surgery for other reasons and patients in shock, patients with the geographic hyperechoic pattern were managed conservatively with no complications.

CONCLUSION

The geographic hyperechoic pattern of liver parenchyma on US examination of trauma patients is a mild injury that, of itself, does not require surgical therapy.

The operative indications for proximal gastrectomy in patients with gastric cancer in the upper third of the stomach

While proximal gastrectomy is often performed for early gastric cancer in Japan, it remains unclear whether or not proximal gastrectomy should be performed for advanced gastric cancer. This study was designed to determine the operative indications for proximal gastrectomy in patients with gastric cancer in the upper third of the stomach. A total of 1691 patients with gastric cancer were reviewed retrospectively from hospital records during the period from 1969 to 1994, and the clinicopathologic characteristics of 82 patients who underwent proximal gastrectomy were compared with those of 150 patients who underwent total gastrectomy. Lymph node metastasis along the lower part of the stomach was observed in gastric cancers which had invaded beyond the muscularis propria of the stomach, but not in those confined to the muscularis propria. Three patients with gastric cancer that had invaded beyond the muscularis propria and metastasized to nodes along the lower part of the stomach were cured by total gastrectomy. However, there was no difference in the postoperative survival rates of the patients treated with proximal gastrectomy and those treated with total gastrectomy, irrespective of tumor stage and depth of invasion. Thus, proximal gastrectomy should be performed for gastric cancer when the depth of invasion is confined to the muscularis propria of the stomach.

Amplification of growth factor receptor genes and DNA ploidy pattern in the progression of gastric cancer

To study the background of oncogene amplification in gastric cancers, we examined the correlation between occurrence of oncogene amplification and DNA ploidy pattern. In 57 primary gastric cancers, amplifications of c-erbB, c-erbB-2, c-met and K-sam genes were investigated by Southern blot analysis, and the DNA ploidy pattern was determined by static cytofluorometry and by flow cytometry. Oncogene amplification was detected in 11 cancers, 10 of which were advanced gastric cancers and 1 was an early differentiated type. The amplification of c-erbB-2 and K-sam genes was found exclusively in differentiated- and undifferentiated-type cancers, respectively. Of the 11 cancers, 5 were DNA-diploid and 6 were DNA-aneuploid. All the 11 tumours with oncogene amplification contained polyploid cell populations (polyploidy), whereas none of the tumours without polyploidy showed oncogene amplification. In differentiated-type cancers the incidence of polyploidy was high in both early and advanced stages, while in undifferentiated-type cancers it was low in early stages but significantly higher in advanced stages. It was shown that amplification of growth factor receptor genes is closely related to the presence of polyploidy, irrespective of any different stemline DNA-ploidy mode. The time-course of oncogene amplification and kinds of genes amplified may differ between differentiated- and undifferentiated-type gastric cancers.