Predictive value of genetic diagnosis for cancer micrometastasis: histologic and experimental appraisal

BACKGROUND

The recently introduced genetic diagnosis of cancer micrometastasis is quite attractive because of its high detection sensitivity. Not infrequently, however, there are marked discrepancies between genetic and conventional histologic diagnoses, especially concerning lymph nodes from colon carcinoma patients. Because the histologic approach has long been relied on in the clinic, the reasons for the differences in results need to be elucidated.

METHODS

Serial sections of genetic diagnosis positive but histologic negative lymph nodes of colon carcinoma patients were prepared for histologic and immunohistochemical studies. To investigate the possible contaminating influence of DNA sequences derived from degraded carcinoma cells from the primary site through the lymphatics, the authors also injected purified DNA of human colon carcinoma cells (SW480) into the foot pads of rats and sequentially examined lymph nodes using genetic diagnosis methodology.

RESULTS

Careful histologic examination of genetic diagnosis positive, histologically negative lymph nodes of colon carcinoma patients confirmed the absence of cancer cells, whereas p53 protein was immunohistochemically demonstrated to be present in the cytoplasm of sinus histiocytes. In the rat experiment, positive reactions were obtained with the inguinal lymph nodes beginning 30 minutes after the injection, and lymph nodes at various sites were subsequently affected, even after a 72-hour period.

CONCLUSIONS

The current study thus suggests that positive results with genetic diagnosis may simply indicate the presence of tumor DNA and do not necessarily mean that viable cancer cells are present. Although the genetic approach may still hold promise for the detection of cancer micrometastases, its predictive value should be carefully assessed clinicopathologically, because its supersensitivity may be associated with a greatly increased false-positive rate.

Continuous ambulatory radionuclide monitoring of left ventricular function: effect of body position during ergometer exercise

We assessed the reliability of a continuous ambulatory radionuclide monitoring system (the VEST system, Capintec, Inc., Ramsey, NJ) for measurement of left ventricular performance during exercise in the upright and supine positions.

METHODS

Sixteen healthy male volunteers (aged 32-46 yr; mean age 37 +/- 4 yr) were studied. All volunteers underwent ergometer exercise testing in both the upright and supine positions, and left ventricular performance was determined with the VEST system.

RESULTS

The resting heart rate, systolic blood pressure, pressure rate product, relative end-diastolic volume, relative end-systolic volume and left ventricular ejection fraction (LVEF) all showed no differences between the upright and supine positions. At peak exercise, the heart rate, systolic blood pressure and pressure rate product showed no differences between the upright and supine positions. In the upright position at peak exercise the relative end-diastolic volume was increased (83% +/- 9% to 91% +/- 11%, p < 0.001); the relative end-systolic volume remained unchanged (34% +/- 3% to 33% +/- 15%), and LVEF was significantly increased from 58% +/- 6% to 66% +/- 11% (p < 0.01). In the supine position at peak exercise, the relative end-diastolic volume remained unchanged (85% +/- 5 to 83% +/- 7%), the relative end-systolic volume was increased (35% +/- 5% to 43% +/- 13%, p < 0.01), and LVEF was decreased from 58% +/- 5% to 48% +/- 17% (p < 0.01). These results indicated inferior data collection by the VEST system in the supine position.

CONCLUSION

Since the detector of the VEST system may be too small, the data collection is impaired during exercise in the supine position by shifting the heart with deep respiration. The VEST system is very useful for determining left ventricular performance when applied in the sitting or upright position. However, in the supine position during exercise, the use of the VEST system should be avoided because it might indicate an artifactual deterioration of left ventricular performance.

Predictive value of genetic diagnosis for cancer micrometastasis: histologic and experimental appraisal

BACKGROUND

The recently introduced genetic diagnosis of cancer micrometastasis is quite attractive because of its high detection sensitivity. Not infrequently, however, there are marked discrepancies between genetic and conventional histologic diagnoses, especially concerning lymph nodes from colon carcinoma patients. Because the histologic approach has long been relied on in the clinic, the reasons for the differences in results need to be elucidated.

METHODS

Serial sections of genetic diagnosis positive but histologic negative lymph nodes of colon carcinoma patients were prepared for histologic and immunohistochemical studies. To investigate the possible contaminating influence of DNA sequences derived from degraded carcinoma cells from the primary site through the lymphatics, the authors also injected purified DNA of human colon carcinoma cells (SW480) into the foot pads of rats and sequentially examined lymph nodes using genetic diagnosis methodology.

RESULTS

Careful histologic examination of genetic diagnosis positive, histologically negative lymph nodes of colon carcinoma patients confirmed the absence of cancer cells, whereas p53 protein was immunohistochemically demonstrated to be present in the cytoplasm of sinus histiocytes. In the rat experiment, positive reactions were obtained with the inguinal lymph nodes beginning 30 minutes after the injection, and lymph nodes at various sites were subsequently affected, even after a 72-hour period.

CONCLUSIONS

The current study thus suggests that positive results with genetic diagnosis may simply indicate the presence of tumor DNA and do not necessarily mean that viable cancer cells are present. Although the genetic approach may still hold promise for the detection of cancer micrometastases, its predictive value should be carefully assessed clinicopathologically, because its supersensitivity may be associated with a greatly increased false-positive rate.

Hyperplastic foveolar gastropathies and hyperplastic foveolar gastritis

Thirteen gastrectomy specimens having diffuse (n = 5), focal (i.e., nodular, n = 6) or combined (n = 2) giant hypertrophic folds at gross examination were reviewed. Of the five specimens with grossly diffuse hypertrophic fundic mucosal folds, two had at histology tortuous foveolar hyperplasia (without intraepithelial lymphocytosis) and prominent glandular cysts; they were classified as Ménétrier's gastropathy. The other three specimens with diffuse foveolar hyperplasia had serrated foveolar infoldings with marked intraepithelial lymphocytosis; they were classified as Ménétrier-like lymphocytic gastritis. Of the six, specimens with multiple mucosal nodules at gross examination, four had focal foveolar hyperplasia with crest depression and no intraepithelial lymphocytosis; they were classified as varioliform gastropathy. The other two specimens with multiple nodules at gross examination had focal foveolar hyperplasia with marked intraepithelial lymphocytosis; they were classified as varioliform gastritis. In the remaining two cases, both diffuse and nodular hypertrophic gastric mucosa were found at gross examination; at histology, both foveolar hyperplasia and intraepithelial lymphocytosis were found. The diffuse or focal distribution of the lesions, the occurrence of intraepithelial lymphocytosis and the architecture of the upper part of the crypts (in diffuse foveolar hyperplasias) were valuable criteria in the differential diagnosis between the various types of foveolar hyperplasia of the stomach.

Necrotizing granulomatous vasculitis of transverse colon and gallbladder

A 52-year-old man suffering neither from allergies or asthma, with necrotizing granulomatous vasculitis (allergic granulomatosis) of the transverse colon and gallbladder is presented. During an emergency laparotomy, segmental necrosis of the mesenteric side of the mid-transverse colon, and a bulky enlarged gallbladder were found. The affected colon was resected and cholecystectomy was performed. Histological findings included necrotizing granulomatous vasculitis of the small- and medium-sized muscular arteries and adjacent veins with tissue infiltration by eosinophils and extravascular eosinophilic granulomas. These histological features were compatible with allergic granulomatous angitis described by Churg and Strauss (CSS). The patient had neither asthma nor involvement of two or more extra-pulmonary organs which is a key clinical criteria of CSS and fulfilled the criteria of eosinophilia alone. Although pulmonary vasculitis was not confirmed in this patient, the histological diagnosis of this patient was definitive CSS. Localised PAN with allergic granulomatosis or an isolated or limited form of CSS based on these clinical features may be an alternative entity.

Platelet-dependent thrombin generation in patients with hyperlipidemia

OBJECTIVES

We evaluated coagulability as determined by platelet-dependent thrombin generation in hypercholesterolemic patients before and after treatment with pravastatin and in hypertriglyceridemic patients to investigate the usefulness of coagulability as an index of atherosclerosis and to determine the importance of treating hyperlipidemia.

BACKGROUND

An understanding of the interaction between platelets and the plasma coagulation system is important for clarifying the mechanism of the procoagulant process.

METHODS

We assessed coagulability in 58 patients with hypercholesterolemia (serum total cholesterol level > or = 220 mg/dl, age 56.5 +/- 1.5 years [mean +/- SEM]), 37 patients with hypertriglyceridemia (serum triglyceride level > or = 200 mg/dl, age 59.5 +/- 1.7 years), 13 patients with hypercholesterolemia plus hypertriglyceridemia (age 51.4 +/- 3.1 years) and 75 normal subjects (age 52.2 +/- 1.7 years). We also studied platelet-dependent thrombin generation in patients with hypercholesterolemia before and after treatment with pravastatin. Calcium chloride was added to 0.5 ml of platelet-rich plasma (150 x 10(9)/liter) to initiate coagulation. Ten microliters of the sample was transferred into 90 microliters of 3.8% sodium citrate at 10-min intervals for 30 min. A chromogenic substrate, S-2238, was added to each sample, and absorbance was measured spectrophotometrically at a wavelength of 405 nm to determine thrombin generation.

RESULTS

Platelet-dependent thrombin generation was increased in patients with hypercholesterolemia and patients with hypercholesterolemia plus hypertriglyceridemia (p < 0.01) compared with patients with hypertriglyceridemia and control subjects. Treatment with pravastatin normalized thrombin generation.

CONCLUSIONS

Hypercholesterolemia, but not hypertriglyceridemia, was associated with increased platelet-dependent thrombin generation. Pravastatin normalized the generation of thrombin.

Migration of hydroxyapatite onlays into the mandible and nasal bone and local bone turnover in growing rabbits

To determine the effects of local bone turnover on the migration of macroporous hydroxyapatite onlays in the nasal bone and mandibular ramus, we performed histomorphometric analyses of the underlying bone area in 41 New Zealand White rabbits from the age of 4 weeks. The hydroxyapatite implants were placed under the periosteum of the right nasal bone (a depository bone onto its periosteal surface and endosteal resorptive) and the mandibular ramus (resorptive onto its outer surface). The corresponding left sides were sham operated. Following fluorescence bone labeling, composite specimens of the hydroxyapatite block including both sides of the nasal bone and mandible were removed at 0 (n = 1), 3, 6, 9, 12, and 16 weeks postoperatively (n = 8, respectively) and processed to yield undecalcified sections. Bone-bone marrow interfaces in the entire area within 200 microns beneath the base of the hydroxyapatite and in the counter-area on the sham-operated side were measured under a light microscope. In all grafted specimens, the hydroxyapatite matrix was directly united with the underlying tissue by bone ingrowth. However, the sinking of the hydroxyapatite graft in the nasal bone was significant at 3 weeks postoperatively and gradually increased thereafter. In the mandible, the sinking became significant at 6 weeks. In the nasal bone, the bone area density beneath the graft showed a time-dependent decrease during the experimental period, but in the mandibular bone, the value was initially decreased at 3 weeks and then recovered to baseline level. In both bones, parameters of bone resorption, such as osteoclast number and osteoclast surface, were significantly increased from 3 weeks. While the parameters of bone formation, such as osteoblast surface and mineralizing surface, were significantly decreased from 3 weeks in the nasal bone, they were significantly increased in the mandible. Mineral apposition rate showed a significant decrease in both bones. Our data indicate that while the bone area density beneath the hydroxyapatite seemed to depend on bone formation, increased bone resorption would be more critical for the remodeling of underlying bony architecture in the migration of the hydroxyapatite graft.

Prognostic value of Doppler transmitral flow velocity patterns in acute myocardial infarction

Doppler transmitral flow patterns are partially dependent on age. We investigated the correlations between the age-adjusted transmitral flow patterns, hemodynamic indexes, and the coronary and clinical outcome in 206 patients with acute myocardial infarction (AMI) and 102 normal control subjects. The peak flow velocity at atrial contraction was significantly lower in 50 of the 206 patients (24%) (low-A group) than in the 102 normal controls. Pulmonary capillary wedge pressure was significantly higher in the low-A group than in the remaining 156 patients with AMI (20 +/- 7 vs 11 +/- 5 mm Hg, p <0.001), and the cardiac index and left ventricular ejection fraction were significantly lower (2.2 +/- 0.6 vs 2.9 +/- 0.7 L/min/m2, p <0.001; 38 +/- 15% vs 52 +/- 13%, p <0.001). The incidence of cardiogenic shock was significantly higher in the low-A group than in the other patients with AMI (42% vs 19%, p <0.001). Regression analysis demonstrated a significant association between decreased atrial filling velocity and increased in-hospital mortality as well as the incidence of heart failure in AMI (p <0.001). The 5-year mortality rate was also significantly higher in the low-A group (p <0.001). The age-adjusted transmitral flow pattern in AMI can identify patients with left ventricular dysfunction, which can lead to a poor prognosis.

Combined intensive chemotherapy and radical surgery for incurable gastric cancer

BACKGROUND

To improve the poor prognosis of patients with advanced incurable gastric cancer, intensive chemotherapy combined with radical surgery was used.

PATIENTS AND METHODS

Thirty patients with incurable gastric cancer were treated with a combination of 5-fluorouracil (370 mg/m2) and leucovorin (30 mg/person), given intravenously for five consecutive days, followed by cisplatinum (70 mg/m2) and etoposide (70 mg/m2) on days 6 and 20, delivered through a catheter placed either in the aorta with its tip at the level of the ninth thoracic vertebra or in the celiac artery. This treatment (FLEP therapy) was repeated twice every 5 weeks. Radical or palliative surgery followed chemotherapy.

RESULTS

The overall response rate to the chemotherapy was 50.0% (15 of 30 patients, 95% confidence limit 0.305-0.671). Nineteen patients (15 with a partial response, three showing no change, and one with progressive disease) underwent surgery. Of these, nine underwent curative surgery and 10 palliative surgery. The median survival time was 6.5 months overall, 12.7 months for responders, and 4.7 months for nonresponders. Long-term survivors were exclusively found among patients with distant lymph node metastasis treated by curative surgery (55.6% at 5 years).

CONCLUSIONS

Favorable results of this small phase II study justify a phase III trial.

Angiographic and coronary risk factor analyses of Japanese patients with ischemic heart disease before age 40--a multicenter cooperative study

Coronary angiographic and risk factor (RF) characteristics were analyzed in 133 Japanese patients with ischemic heart disease (IHD) who were less than 40 years old and who had undergone coronary angiography (CAG) during the past 10 years at six university hospitals in the Tokyo area. We compared the coronary angiographic characteristics of the subject group with those of 216 controls with coronary sclerosis detected by CAG who were more than 40 years old (older control group) and the RF characteristics with those of 133 sex- and age-matched volunteers (younger control group). Sixty seven percent of the subjects (89 cases) were diagnosed as having myocardial infarction (MI) and 33% (44 cases) had angina pectoris (AP). Coronary artery disorders in this group consisted of 103 (77%) cases of coronary sclerosis, 20 (15%) cases of coronary spasm and 10 (8%) cases of miscellaneous diseases, eg, possible vasculitis with connective tissue disease, congenital anomalies, etc. The incidences of significant (> or = 75%) sclerotic narrowing in 0 vessels (31%) and 1 vessel (49%) in the subject group were significantly (p < 0.01) higher than those in the older control group, while the incidence of multivessel disease was significantly (p < 0.05) less in the subject group than in the older control group. The incidences of the following coronary risk factors were significantly (p < 0.05) higher in the subjects than in the younger controls: smoking (83% vs 35%), hypercholesteremia (44% vs 10%), obesity (31% vs 9%), hypertension (29% vs 3%), familial IHD (28% vs 7%) and diabetes mellitus (19% vs 2%). Thus, zero- or single-vessel disease predominated in the younger subject group and the prevalence of coronary risk factors was significantly higher in the subject.

Leuchtenberger bodies in flat adenomas of the colorectal mucosa: a comparison between Japanese and Swedish patients

The dysplastic epithelium of flat colorectal adenomas was found to contain DNA inclusion granules, known as Leuchtenberger bodies (LB). Hematoxylin and eosin-stained sections of 263 colorectal flat neoplastic lesions (i.e., flat adenomas, and flat adenocarcinomas) collected in Japan and Sweden were scrutinized for the presence of such intraepithelial inclusions. LB were recorded in 87.1% of the 263 flat colorectal neoplastic lesions. The frequency of flat colorectal lesions having LB was similar in Japan (160 of 178 or 89.8%) to that in Sweden (69 of 85 flat lesions or 81.2%), suggesting that the occurrence of LB may not be influenced by race or environment. Direct immunoperoxidase detection of nuclear DNA fragmentation and transmission electron microscopy studies indicated that the inclusions contained apoptotic material. The semiquantitative assessment of histochemically labeled apoptotic granules indicated that the number of lesions having moderate to large numbers of apoptotic granules (++/ ) was higher in flat adenomas with high-grade dysplasia, suggesting that the occurrence of these granules may be related to the degree of severity of the dysplastic process. A better knowledge of LB may improve our understanding of the possible relationship between apoptosis, host immune response and carcinogenesis in flat colorectal adenomas.

Surgical treatments of chronic idiopathic thrombocytopenic purpura and prognostic factors for splenectomy

To determine the prognostic factors for splenectomy in patients with chronic idiopathic thrombocytopenic purpura (ITP), 26 consecutive patients who had undergone splenectomy as a treatment for ITP in the last 20 years were investigated retrospectively. Predictive values of age, sex, the interval between diagnosis and surgery, presence of antiplatelet antibodies or accessory spleen, bleeding time, response to corticosteroids, response to high-dose immunoglobulin, weight of spleen, serum platelet-associated immunoglobulin G, preoperative maximal platelet count, and preoperative minimal platelet count were examined with multivariate analysis by multiple regression. Age less than 50 years at surgery, platelet count of 100 x 10(9)/l or more in response to high-dose immunoglobulin, and a maximal platelet count of 100 x 10(9)/l or more before splenectomy were favorable prognostic factors (p < 0.05). The correlation coefficient, sensitivity, specificity, and positive-predictive value of the analyzed multiple regression based on prognostic factors were 0.885, 68.8%, 85.7% and 91.7%, respectively. In conclusion, splenectomy is an effective treatment for younger patients, large maximal preoperative platelet counts and preoperative immunoglobulin dependence. Multivariate function analysis was useful for predicting outcome.

Genetic mechanisms in esophageal carcinogenesis: frequent deletion of 3p and 17p in premalignant lesions

Although dysplasia of the esophagus is thought to be the precursor lesion of esophageal squamous cell carcinoma (ESC), the sequence of genetic events during esophageal carcinogenesis is unclear. Using the polymerase chain reaction, we examined allelic losses at microsatellite loci in DNAs isolated from 106 lesions among 32 patients with ESC. Allelic losses on 3p or 17p occurred frequently even in dysplastic lesions (9 of 21 and 13 of 24 samples, respectively) including lesions with mild dysplasia (3p, 4 of 10 samples; 17p, 6 of 14 samples, respectively), and allelic losses on these chromosomal arms were also observed in cancerous tissues. We also detected allelic losses of the short and long arms of chromosome 9 at a low frequency in lesions with mild dysplasia and often in lesions with severe dysplasia and in intraepithelial cancers. Our results suggested that inactivation of tumor suppressor genes on 3p and 17p occurs at a very early stage of esophageal carcinogenesis and that genes on 9p and 9q are likely to play important roles in malignant changes. Comparison of the genetic alterations in precancerous dysplastic lesions with those in carcinomas supports the idea that ESC arises from the dysplastic lesion.

Platelet-dependent thrombin generation in patients with diabetes mellitus: effects of glycemic control on coagulability in diabetes

OBJECTIVES

This study sought to assess the usefulness of platelet-dependent thrombin generation as an index of coagulability in diabetes and to determine the effect of glycemic control on coagulability in diabetes.

BACKGROUND

It is important to investigate the interaction of platelets and the coagulation factors to clarify the processes of the coagulation system in detail.

METHODS

Platelet-rich plasma (150 X 10(9)/liter), 0.5 ml, was prepared, and 40 mmol/liter of calcium chloride was added to initiate clotting. S-2238 was added to each sample in a microtiter plate every 10 min, and the absorbance of the released color product at 2 min was measured spectrophotometrically at a wavelength of 405 nm using a microtiter plate reader as thrombin generation. We measured the platelet-independent thrombin generation in patients with non-insulin-dependent diabetes mellitus grouped according to glycemic control.

RESULTS

Platelet-dependent thrombin generation at 30 min after calcium chloride addition was significantly higher in 23 patients with poorly glycemic-controlled non-insulin-dependent diabetes mellitus without complications, such as diabetic retinopathy, nephropathy and neuropathy (hemoglobin [Hb] A1c >/= 9.0%) than in 46 healthy normal subjects (448 +/- 75 vs. 165 +/- 28 mU/min, p < 0.001). Thrombin generation in 31 well controlled diabetic patients without complications (Hb A1c < 9.0%) was intermediate (240 +/- 72 mU/min) between those of the poorly controlled group and healthy normal subjects. Platelet-poor plasma from diabetic patients increased platelet-dependent thrombin generation in normal subjects.

CONCLUSIONS

Coagulability is evidently enhanced in patients with non-insulin-dependent diabetes mellitus compared with that in healthy normal subjects on the basis of assessments of the platelet-dependent thrombin generation, and good glycemic control may help to correct a hypercoagulable state in diabetic patients.

Deletion mapping on chromosome 1p in well-differentiated gastric cancer

To define the region on the short arm of chromosome 1 that is thought to include one or more tumour-suppressor genes for gastric cancers, we carried out loss of heterozygosity (LOH) studies in 26 gastric adenocarcinomas, using three restriction fragment length polymorphism (RFLP) markers and nine microsatellite markers. All tumours were informative with at least one locus; three revealed replication errors (RERs) at multiple microsatellite loci, and interstitial or telomeric allelic deletions were observed in 12 cases. Deletion mapping of these tumours defined a commonly deleted region between two loci, D1S201 and D1S197, that are 13 cM apart. As two loci within the commonly deleted region, D1S57 (pYNZ2) and D1S62 (pTHI54), were mapped respectively to 1p35 and 1p34.3 by fluorescence in situ hybridisation, we conclude that a locus likely to contain a tumour-suppressor gene for gastric cancer is located within a 13 cM region encompassing two chromosomal bands.

Flat adenomas and flat adenocarcinomas of the colorectal mucosa in Japanese and Swedish patients. Comparative histologic study

PURPOSE

In recent years, flat adenomas of the colorectal mucosa have been intensively investigated by Japanese pathologists. Results of that work indicate that flat adenomas may antedate the development of colorectal carcinomas. Because of differences in the histologic definition of flat adenomas with severe dysplasia and with intramucosal carcinoma within the group, one single observer having both Western and Asian training in pathology reviewed the material.

METHODS

A total of 287 flat colorectal lesions were reviewed: 109 from the Karolinska Hospital, Stockholm, 137 from the Tokyo Medical and Dental University (TMDU) (which included 5 cases from the Nagoya City University), and 41 from the Cancer Institute (CI), Tokyo. Lesions were histologically classified following strict histologic criteria. Thus, flat adenomas were divided into those having low-grade dysplasia (LGD; having dysplastic cells in the deeper half of the epithelium), high-grade dysplasia (HGD; dysplastic cells were found even in the superficial half of the epithelium), intramucosal carcinoma (dysplastic glands displayed molding with buddings and often a cribriform pattern), and adenocarcinoma (braking through the muscularis mucosa, with neoplastic cells in the submucosal layer or deeper).

RESULTS

Whereas in Stockholm only 14.7 percent of lesions had HGD, as much as 56.9 percent and 56.1 percent, respectively, had HGD at the two Tokyo Hospitals. Intramucosal carcinomas were not found in the Stockholm material but occurred in 2.2 percent of lesions seen at TMDU and in 4.9 percent of those seen at the CI. Notably, only 2.7 percent of the specimens at Karolinska Hospital had invasive adenocarcinoma, but it was seen in as many as 4.4 percent at TMDU and 21.9 percent at the CI.

CONCLUSIONS

This study indicates that there were histologic differences between flat neoplasias of the colorectal mucosa harvested in Stockholm and Tokyo. In Japan lesions were obviously more advanced (in terms of HGD) and more aggressive (in terms of intramucosal and submucosal invasion). The cause for the differences found in those two disparate geographic regions remains poorly understood. The results, however, may help us understand some of the unclear points and discussions appearing in the literature on this subject.

Infrequent replication errors at microsatellite loci in tumors of patients with multiple primary cancers of the esophagus and various other tissues

Patients with esophageal cancer are at high risk of developing other primary tumors, especially squamous cell carcinoma in the head and neck. Heavy smoking and excessive consumption of alcohol are considered to be crucial environmental risk-factors for development of these multiple primary cancers. To investigate whether any genetic background, such as defects in the DNA-mismatch repair system, may influence the development of these multiple primary tumors, we examined replication errors (RER) at six microsatellite loci in DNAs of 46 tumors from 33 patients who had developed primary cancers in various tissues in addition to the esophagus. RER(+) (RER-positive) phenotype was observed in three tumors in two patients of the 33 patients examined. Our results suggested that development of multiple primary tumors in these patients would not be affected by an abnormality in the DNA repair system(s) detected as the RER phenotype. However, it is noteworthy that a single patient who developed multiple cancers revealed RER(+) phenotypes at multiple microsatellite loci in both tumors, indicating that a defect in the DNA repair gene(s) may have played an important role in the development of the tumors in this patient.

Genetic diagnosis of lymph-node metastasis in colorectal cancer

If a regional lymph node taken during surgery for colorectal cancer is found to be free of tumour on histological examination this is taken to be a good sign. However, conventional staining may not be sensitive enough. Mutant-allele-specific amplification (MASA) is a technique that can detect, at the level of an individual cell, micrometastases to lymph nodes that are histologically diagnosed as negative. To examine the prognostic significance of such genetically detectable tumour cells we screened 120 colorectal cancers from patients who had no histologically detectable lymph-node metastasis at the time of surgery for mutations in K-ras (codons 12, 13, and 61) or p53 (exons 5-8). Somatic mutations were identified by MASA in 71 tumours. We next examined preserved tissues from corresponding regional lymph nodes, using MASA to look for the specific mutation found in the primary. Of 37 patients with genetically positive lymph nodes 27 had had a tumour recurrence within 5 years of surgery; none of the 34 patients who were MASA negative for lymph node metastasis had had a recurrence. Genetic diagnosis of lymph node metastasis may be a useful prognostic factor in colorectal cancer, and it could also serve as a selective marker for intensive postoperative adjuvant chemotherapy.

Can esophagectomy cure cancer of the thoracic esophagus involving the major airways?

To evaluate the effects of aggressive operation for esophageal cancer invading the trachea and main bronchi, we investigated retrospectively 62 patients with proven tracheobronchial involvement who underwent thoracotomy for esophagectomy between 1973 and 1993. We operated unless the tumor was assessed to be definitely unresectable. Esophagectomy was possible in 55 patients, and the resectability rate was 95% after preoperative computed tomography and bronchoscopy became routine. After esophagectomy, no residual cancer lesion was recognizable macroscopically in 53% of patients. The hospital mortality rate in esophagectomy cases was 7% in the past 8 years. The outcome in patients who underwent curative resection was significantly favorable (p < 0.0001), and the 2-year survival was 51%. The patients with nonresectable cancer all died within 6 months compared with a 23% 1-year survival rate for palliative esophagectomy cases (p < 0.006). Among patients with tracheobronchial involvement assessed as resectable on computed tomography and bronchoscopy, a considerable proportion benefited from aggressive therapy with esophagectomy. The possibility of complete cure was high, especially when the cancer responded well to preoperative therapy and no lymph nodes were involved.