Takeshi Okuda

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.

Postoperative changes in body composition after gastrectomy

Nutritional status is one of the most important clinical determinants of outcome after gastrectomy. The aim of this study was to compare changes in the body composition of patients undergoing laparoscopyassisted gastrectomy (LAG), distal gastrectomy (DG), or total gastrectomy (TG). Total body protein and fat mass were measured by performing a multifrequency bioelectrical impedance analysis using an inBody II machine (Biospace, Tokyo, Japan) in 108 patients (72 men, 36 women) who had undergone LAG (n = 24), DG (n = 39), or TG (n = 45). Changes between the preoperative data and results obtained on postoperative day 14 and 6 months after surgery were then evaluated. The mean preoperative body weight of the subjects was 57.6 +- 10.7 kg, the mean body mass index was 22.5 +- 3.4 kg/m2, and the mean fat % was 24% +- 7%. In the immediate postoperative period (14 days), the body weight loss in the LAG group was significantly lower than in the DG and TG groups (2.5 +- 0.9 kg vs. 3.5 +- 1.8 kg and 4.0 +- 1.9 kg, respectively; P +- 0.0001). The body composition studies demonstrated a loss of total body protein rather than fat mass. Six months after surgery, body weight was not significantly different from preoperative values in the LAG and DG groups (-1.2 +- 3.8 kg and -1.8 +- 4.7 kg, respectively), but had decreased by 8.9 +- 4.9 kg in the TG group (P = 0.0003). A body composition analysis revealed a loss of fat mass in the DG and TG groups. The patients who underwent gastrectomy lost body protein mass during the early postoperative period. The type and extent of surgery has an effect on long-term body mass and composition. Bioelectric impedance analysis can be used to assess body composition and may be useful for nutritional assessment in patients who have undergone gastrectomy.

Inflammation of the gastric remnant after gastrectomy: mucosal erythema is associated with bile reflux and inflammatory cellular infiltration is associated with Helicobacter pylori infection

BackgroundControversy exists concerning the role of bile reflux and Helicobacter pylori (H. pylori) infection in the development of inflammation of the gastric remnant after gastrectomy. This study was designed to investigate association of bile reflux and H. pylori infection or both with inflammatory changes in the gastric remnant.MethodsA questionnaire on GI symptoms was returned by 200 gastrectomy patients, and 24-h bilirubin monitoring in the gastric remnant was performed on 55 patients with Bilitec 2000. Upper GI endoscopy evaluated reflux gastritis in the gastric remnant, and the presence of H. pylori infection and chronic, active inflammatory cellular infiltration in the biopsy specimens were examined microscopically with the updated Sydney system.ResultsNo difference in the incidence of GI symptoms was observed among individual gastrectomy patients. Bile reflux was lower in patients who had undergone a gastrectomy with jejunal interposition, a pylorus-preserving gastrectomy, and a gastrectomy with Roux–Y anastomosis than those who had undergone a Billroth-II (B-II) anastomosis (P < 0.05). Endoscopy showed positive correlation between mucosal erythema and bile reflux (P < 0.001). No correlation was observed between the mucosal erythema and chronic and active inflammatory cellular infiltration. Infection of H. pylori correlated with chronic and active inflammatory cellular infiltration (P < 0.001). Bile reflux did not correlate with the severity of chronic and active inflammatory cellular infiltration or H. pylori infection.ConclusionsBile reflux into the gastric remnant was observed by Bilitec 2000. Mucosal erythema and chronic, active inflammatory cell infiltration in the gastric remnant after gastrectomy may be caused by bile reflux or H. pylori infection, respectively.

Significance of serum markers pepsinogen I and II for chronic atrophic gastritis, peptic ulcer, and gastric cancer.

Chronic atrophic gastritis (CAG) is closely correlated with gastric cancer and is predominant in Japan. Epidemiologically, food habits are the primary factor in both CAG and gastric cancer. Two potential serum markers for CAG have recently been investigated, i.e., the concentration of serum pepsinogen (PG) and the presence of serum antibodies against Helicobacter pylori. Serum PG I and II and the PG I:PG II ratio have been reported to be useful as indicators of recurrent peptic ulcer and for screening of patients at risk from gastric cancer. In this study, we examined PG I and II in serum from 483 patients by RIA (DAINABOT), and endoscopic examination performed in the same patients before serological assay revealed CAG in 68, peptic ulcer in 91, and gastric cancer in 48. Analysis of the mean values according to patients age showed that CAG patients in their forties to eighties had low (< 40 ng/ml) levels of PG I, peptic ulcer patients in their teens to eighties had high (> or = 70 ng/ml) levels, except for those in their seventies, and gastric cancer patients in their twenties to sixties had low (< 3.0) PG I:PG II ratios, except for those in their sixties. Thus serum PG assay has potential utility for detection of CAG, peptic ulcer, and gastric cancer.

Sequential changes in the cell mediators of peritoneal and wound fluids after surgery.

The concentrations of cell mediators in the peritoneal and wound fluids of patients who underwent abdominal surgery or mastectomy were determined sequentially and compared with the concomitant changes in blood components. The level of interleukin-6 (IL-6) in the peritoneal and wound fluids was significantly higher than the plasma level after gastrectomy (P<0.001), cholecystectomy (P<0.05), and mastectomy (P<0.05), although the level of plasma IL-6 was also higher postoperatively than before surgery (P<0.001, P<0.05). Significantly higher levels of tumor necrosis factor-α were detected in the peritoneal and wound fluids (P<0.01, P<0.05, respectively) after surgery despite its absence in plasma. A platelet-specific protein and a protein specific for fibroblasts were also measured. Thus, mediators derived from various cells were shown to be present in human peritoneal and wound fluids, indicating that the local production of these mediators plays an important role in the process of tissue repair.

Detection of serum IgG antibody againstHelicobacter pylori from childhood in a Japanese population

Epidemiological evidence has shown that seropositivity forHelicobacter pylori in the stomach is positively correlated with the incidence of gastric cancer. In this study, we investigated serum IgG antibody againstH. pylori in asymptomatic Japanese subjects by an enzyme-linked immunoassay (ELISA) method (Serion, Wuerzburg, Germany). We noted two characteristics: (1) Seropositivity was seen in 41% of individuals aged less than 1 year, and in 9% of those aged 1–2 years, indicating the possibility that IgG antibody in infancy is derived from the mother. (2) Seropositivity was seen in 35% of individuals aged 15–19 years compared to 70% in those aged 20–24 years, indicating the spread ofH. pylori infection with age.

Stimulatory effect of EGF and inhibitory effect of sialoadenectomy on growth of an EGF receptor-hyperproducing human gastric cancer xenograft in nude mice

We recently established epidermal growth factor (EGF) receptor-hyperproducing human gastric cancer xenografts in nude mice. The present study was designed to examine whether the growth of a xenograft having 1,098 ±276fmol/mg protein of EGF receptor would either be stimulated by the administration of EGF or inhibited by the removal of the submandibular glands (sialoadenectomy) which contain a large amount of EGF. A miniosmotic pump containing 2 μg or 20 μg of EGF was implanted on the back of the animals in the EGF stimulation experiments. The tumor growth was stimulated by the administration of EGF (P < 0.01), and the doubling time of the tumor was reduced relative to the controls (P < 0.01). Both the mitotic indices and the bromodeoxyuridine (BrdU)-labeling indices of the tumor were higher than those of the controls (P < 0.01). Tumor growth inhibited by the sialoadenectomy (P < 0.05) while the tumor doubling time was prolonged compared with the sham-operated mice (P < 0.05). These results suggest that the growth of a human gastric cancer xenograft may be modulated by EGF.

The presence of tumor necrosis factor-α and its antibody in the sera of cachexic patients with gastrointestinal cancer

Although cancer cachexia has been shown to involve several cytokines, the tumor necrosis factor-α (TNF) has rarely been detected in such patients. In this study, sera from 21 patients with cancer cachexia were examined for the presence of TNF and the anti-TNF antibody using an enzyme-linked immunosorbent assay (ELISA) and Western blotting, respectively. All of the patients had recurrent cancer and manifested the characteristics of progressive body weight loss. TNF was found in the sera of four patients (20%) at levels ranging from 10.4 to 53.1 pg/ml, while a positive reaction for the anti-TNF antibody was detected in the sera from six patients (30%), two of whom showed both TNF and its antibody. Thus, either TNF or the anti-TNF antibody was present in the sera from 8 of 21 patients (40%). The results of this study indicate that TNF may be present in the circulation of at least 40% of cachexic patients, and suggest that it may be one of the main mediators of cancer-associated cachexia.

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.

Prevention of Growth of a Human Gastric Cancer Xenograft in Nude Mice with Anti-EGF Receptor Antibody

Previously, we established seven human gastric cancer xenografts with different concentrations of EGF receptor nude mice. A close correlation was seen between the concentration of125 I-EGF binding activity and the doubling time of these tumors. The present study was therefore designed to clarify whether anti-EGF receptor antibody would prevent the growth of the xenografts. Twenty micrograms of anti-EGF receptor monoclonal antibody (MoAb528) in an Alzet mini-osmotic pump, which releases its contents over 2 weeks, was given to each animal bearing a xenograft (NMS12) containing 1,000 fmol/mg protein EGF receptor. The treatment inhibited tumor growth completely when it was started on the day after tumor cell inoculation, whereas tumors in control animals grew to 0.8 to 1.0 g in 3 weeks. No toxic effects on the liver, kidney or spleen were evident either macro- or microscopically. The growth of an EGF receptor-hyperproducing xenograft derived from human gastric cancer in nude mice was thus shown to be inhibited by MoAb528. Therefore, MoAb528 is suggested to be an effective antitumor agent against gastric cancer showing overexpression of EGF receptor.