Ken-ichi Mafune

Primary undifferentiated small cell carcinoma of the esophagus

Abstract We histologically examined undifferentiated small cell carcinoma of the esophagus from 21 patients and used immunohistochemical methods for detection of chromogranin A and p53, bc1–2, and Rb oncoproteins. Nine (43%) of the 21 carcinomas consisted solely of undifferentiated cells, but heterogeneous components of in situ or invasive squamous cell carcinoma or mucoepidermoid carcinoma were observed in the other 12 (57%) tumors. Squamous cell carcinoma in situ was observed in the mucosa adjacent to the main tumor in 7 (50%) of the 14 resected esophageal specimens. An admixture of invasive squamous cell carcinoma and undifferentiated carcinoma was observed in 4 (19%) of the 21 tumors, and mucoepidermoid carcinoma was noted in one case. Chromogranin A staining yielded a positive reaction in two (10%) undifferentiated components but was negative in all heterogeneous components. Multiple sites of p53 immunopositivity were seen in the undifferentiated component of 17 (81%) of the 21 tumors, as well as in the in situ or invasive squamous cell carcinoma or mucoepidermoid carcinoma components of 9 (75%) of 12 tumors. Seven (33%) of the 21 tumors showed positive bc1–2 immunoreactivity in the small cell component, but all of the heterogeneous components were negative. Rb protein immunoreactivity was observed in the small cell component of one (5%) case and in 9 (75%) of the 12 heterogeneous components. Six (86%) of the seven in situ squamous cell carcinoma components were positive for Rb protein. Eighteen (86%) of the 21 patients died within 24 months of diagnosis. Two patients (10%) who survived for more than 24 months had received chemotherapy.

Lymph node metastasis and preoperative diagnosis of depth of invasion in early gastric cancer.

Background. No reports have, to date, focused on the relationship between preoperative determination of the depth of invasion and lymph node metastasis. The present study, under the leadership of the Japanese Gastric Cancer Association, was designed to form a basis for decision making in limited treatment for early gastric cancer (EGC). Methods. From eight major hospitals in Japan, 2672 gastric cancers whose preoperative depth of invasion was mucosal(M-cancer), and 6209 EGCs, consisting of 3584 mucosal(m-) and 2625 submucosal(sm-) cancers, were collected by questionnaire. All registered patients underwent gastrectomy with D1 or more extensive lymphadenectomy between 1985 and 1998. Results. The accuracy of preoperative diagnosis of depth of invasion of M-cancers was 80.2% (2144/2672). However, of the total of 2432 M-cancers in which no nodal involvement was observed intraoperatively (N0), histological examination of the resected specimens confirmed that lymph node metastasis was absent in 2353 (96.8%). The frequencies of lymph node metastasis in early gastric, m-, and sm-cancers were 8.9%, 2.5%, and 17.6%, respectively. Node involvement was associated with a higher frequency of undifferentiated than differentiated histology, as well as with greater tumor size. The incidences of lymph node metastasis in m-cancers with a diameter of less than 4 cm, and in sm-cancers with a diameter below 1 cm were 1.3% (37/2837) and 4.9% (4/82), respectively. These metastases rarely extended beyond the first tier. Conclusion. N0 and M-cancers, m-cancers less than 4 cm in diameter, and sm-cancers no larger than 1 cm in diameter may be appropriate indications for limited surgery.

Is there a set of histologic changes that are invariably reflux associated

Many histologic changes have been described in the esophageal squamous mucosa in patients with gastroesophageal reflux disease (GERD), including dilated intercellular spaces, balloon cells, intrapapillary vessel dilation, elongated papillae, basal cell hyperplasia, acanthosis, intraepithelial eosinophils, Langerhans cells, and p53 protein overexpression. To define a set of histologic changes that are invariably reflux associated, we examined the histologic changes in esophageal specimens from normal controls, patients with GERD, patients without GERD but with a suspicion of other pathology, and patients with esophageal carcinoma. We also examined biopsy specimens from sites with differing endoscopic features, including cloudy white and reddened mucosa. A definitive set of reflux-associated histologic changes could not be defined from the small number of biopsy specimens examined in the present study. Histologic changes indicative of GERD are likely to be found somewhere in the esophagus in all patients with GERD, but these changes are nonspecific. A set of histologic changes that are invariably reflux associated may exist, but these changes are nonspecific. To develop a set of characteristic reflux-associated features, endoscopists may perform targeted biopsies from several sites with various endoscopic features and at different stages of disease.

A novel variant of human Grb7 is associated with invasive esophageal carcinoma.

The cDNAs of a putative growth factor-bound (Grb) 7 signal transduction molecule and Grb7V novel splice variant were isolated from an invasive human esophageal carcinoma. Although both Grb7 isoforms share homology with the Mig-10 cell migration gene, the Grb7V isoform lacks 88 base pairs in the C terminus; the resultant frame shift leads to substitution of an SH2 domain with a short hydrophobic sequence. The wild-type Grb7 protein, but not the Grb7V isoform, is rapidly tyrosyl phosphorylated in response to EGF stimulation in esophageal carcinoma cells. Analysis of human esophageal tumor tissues and regional lymph nodes with metastases revealed that Grb7V was expressed in 40% of Grb7-positive esophageal carcinomas. More importantly, Grb7V expression was enhanced after metastatic spread to lymph nodes as compared to the original tumor tissues. Finally, transfection of an antisense Grb7 RNA expression construct lowered endogenous Grb7 protein levels and suppressed the invasive phenotype exhibited by esophageal carcinoma cells. These findings suggest that Grb7 isoforms are involved in cell invasion and metastatic progression of human esophageal carcinomas.

Chemopreventive Effect of Peroxisome Proliferator–Activated Receptor γ on Gastric Carcinogenesis in Mice

Peroxisome proliferator-activated receptor gamma (PPARgamma) is known to be expressed in several cancers, and the treatment of these cancer cells with PPARgamma ligands often induces cell differentiation and apoptosis. Recently, the chemopreventive potential of PPARgamma ligands on colon carcinogenesis was reported, although the effect of PPARgamma on colon carcinogenesis and the mechanism of the effect remain controversial. In this study, we attempted to elucidate the role of PPARgamma in gastric carcinogenesis and explored the possible use of PPARgamma ligand as a chemopreventive agent for gastric cancer. N-methyl-N-nitrosourea (MNU, 240 ppm) was given in drinking water for 10 weeks to induce gastric cancer in PPARgamma wild-type (+/+) and heterozygous-deficient (+/-) mice, followed by treatment with PPARgamma ligand [troglitazone, 0.15% (w/w) in powder food] or the vehicle alone for 42 weeks. At the end of the experiment, PPARgamma (+/-) mice were more susceptible to MNU-induced gastric cancer than wild-type (+/+) mice (89.5%/55.5%), and troglitazone significantly reduced the incidence of gastric cancer in PPARgamma (+/+) mice (treatment 55.5%/vehicle 9%) but not in PPARgamma (+/-) mice. The present study showed that (a) PPARgamma suppresses gastric carcinogenesis, (b) the PPARgamma ligand troglitazone is a potential chemopreventive agent for gastric carcinogenesis, and (c) troglitazones chemopreventive effect is dependent on PPARgamma.

Quantitative detection of micrometastases in the lymph nodes of gastric cancer patients with real-time RT-PCR: A comparative study with immunohistochemistry

Histologic examination lacks the sensitivity to detect micrometastases in gastric cancer lymph nodes. In the present study, we applied a real‐time RT‐PCR approach to the quantitative detection of micrometastases in gastric cancer lymph nodes and compared diagnostic power with routine histology and immunohistochemistry. We studied 392 lymph nodes from 21 gastric cancer patients who underwent curative surgery. Real‐time quantitative RT‐PCR was performed on a LightCycler instrument using a hybridization probe for carcinoembryonic antigen (CEA) and cytokeratin‐20 (CK20) as marker genes. Immunohistochemistry with antibodies to wide‐keratin was also performed in the lymph nodes to compare the sensitivity and specificity. Median (average) values of CEA mRNA in lymph nodes in patients with histology+, immunohistochemistry+/histology−, immunohistochemistry−/histology− and negative control results were 4,600 (16,000), 200 (400), 0 (9.8) and 0 (0.6), respectively. There were some false‐negative results with simple CEA and CK20 real‐time RT‐PCR due to the presence of low gene‐expressing gastric cancers as revealed by CEA and CK20 immunohistochemistry. CEA in combination with CK20 (duplex) real‐time RT‐PCR partially covered this weakness. Consequently, all 71 histology+ lymph nodes were positive for duplex real‐time RT‐PCR as well as wide‐keratin immunohistochemistry. Positivity rates by histology, wide‐keratin immunohistochemistry and duplex real‐time RT‐PCR were 18.0% (71/392), 20.9% (82/392) and 25.8% (101/392), respectively. In 2 of 8 patients with pT1N0, positive lymph nodes were observed by real‐time RT‐PCR but not by immunohistochemistry. These results indicate that duplex quantitative real‐time RT‐PCR is the most sensitive method for detecting micrometastases and useful for evaluating the prognostic significance of lymph node micrometastasis in gastric cancer patients.

Correlation of telomere lengths in normal and cancers tissue in the large bowel.

The hypothesis that telomeres in colorectal cancer cells exhibit age-related shortening, as in normal cells of the colorectal epithelium, was tested with samples of non-cancerous mucosa and cancer tissue from 124 patients (aged 29-97 years). Shortening with aging could be demonstrated for both normal and cancer tissues; regression analysis showed rates for length reduction of 44 and 50 base pair/year, respectively. Straight, essentially parallel, lines were obtained for the two cases, normal tissue values being about 2 kilobase pairs (kbp) higher, with a significant correlation between data at the individual patient level.

Telomerase activity in esophageal carcinoma

Telomerase is a ribonucleoprotein that synthesizes telomeric DNA. Immortalized and carcinoma cells show no loss of telomere length during cell division. Telomerase activity has been demonstrated in carcinomas of various organs, but not in nonneoplastic tissues. In patients with esophageal carcinoma, no data have been reported concerning the relationship between telomerase activity and clinicopathological findings.

Accuracy of linear-array EUS for preoperative staging of gastric cardia cancer

BACKGROUND The feasibility of a less invasive operation for early stage cancer of the gastric cardia with a low frequency of lymph node involvement has been previously demonstrated by us. Precise discrimination among mucosal, submucosal, and advanced cancers, as well as accurate evaluation of the proximal tumor margin are prerequisites for such stage-specific treatment. EUS is considered the most reliable staging modality. However, there is no EUS study specifically of cardia cancer. METHODS Forty-five patients with gastric cardia cancer who underwent gastrectomy with at least first-tier lymphadenectomy were retrospectively analyzed. The results of preoperative linear-array echoendoscopy (7.5 MHz) with respect to cancer depth, lymph node involvement, and esophageal invasion were compared with postoperative histopathologic findings. RESULTS Overall diagnostic accuracy for depth of invasion was 71%. Sensitivity for T1, T2, and T3 lesions was 100%, 31% and 75%, respectively. Overstaging of T2 cancers was the main diagnostic error. Mucosal (pT1-m) and submucosal (pT1-sm) cancers were correctly discriminated in 81% of patients. Diagnostic accuracy for lymph node involvement was 80%. EUS had positive and negative predictive values of 90% and 80%, respectively, for esophageal invasion. CONCLUSIONS For gastric cardia cancer, the linear-array echoendoscope yielded satisfactory results with respect to depth of invasion, lymph node involvement, and esophageal invasion evaluation. The information obtained is useful to the performance of stage-specific treatment.

Basaloid‐Squamous Carcinoma of the Esophagus with Marked Deposition of Basement Membrane Substance

A 71 year old Japanese man with basaloid‐squamous carcinoma of the esophagus is reported. The carcinoma contained basaloid cells, a few small cornified foci, and a large amount of eosinophilic hyaline substance, which reacted positively upon periodic acid Schiff, type IV collagen, and laminin staining. Ultrastructural examination revealed markedly replicated basement membranes (BM). The morphological findings suggested that this tumor secreted abundant BM substance. Small nests of cancer cells were attached to the dysplastic esophageal epithelium. The tumor cells exhibited negative staining for mucin, secretory component, lactoferrin, and carcinoembryonic antigen. These findings, as well as the observed keratini‐zation and attachment between the carcinoma nests and mucosal epithelium, indicate that the tumor originated in the mucosal epithelium of the esophagus. Acta Pathol Jpn 41: 59–64, 1991.