Aberrant CpG-island methylation has non-random and tumour-type-specific patterns.

CpG islands frequently contain gene promoters or exons and are usually unmethylated in normal cells. Methylation of CpG islands is associated with delayed replication, condensed chromatin and inhibition of transcription initiation. The investigation of aberrant CpG-island methylation in human cancer has primarily taken a candidate gene approach, and has focused on less than 15 of the estimated 45,000 CpG islands in the genome. Here we report a global analysis of the methylation status of 1,184 unselected CpG islands in each of 98 primary human tumours using restriction landmark genomic scanning (RLGS). We estimate that an average of 600 CpG islands (range of 0 to 4,500) of the 45,000 in the genome were aberrantly methylated in the tumours, including early stage tumours. We identified patterns of CpG-island methylation that were shared within each tumour type, together with patterns and targets that displayed distinct tumour-type specificity. The expression of many of these genes was reactivated by experimental demethylation in cultured tumour cells. Thus, the methylation of particular subsets of CpG islands may have consequences for specific tumour types.

Concerted nonsyntenic allelic loss in human colorectal carcinoma.

Familial polyposis coli (FPC) is caused by an autosomal dominant gene on chromosome 5, and it has been proposed that colorectal cancer in the general population arises from loss or inactivation of the FPC gene, analogous to recessive tumor genes in retinoblastoma and Wilms' tumor. Since allelic loss can be erroneously scored in nonhomogeneous samples, tumor cell populations were first microdissected from 24 colorectal carcinomas, an additional nine cancers were engrafted in nude mice, and nuclei were flow-sorted from an additional two. Of 31 cancers informative for chromosome 5 markers, only 6 (19%) showed loss of heterozygosity of chromosome 5 alleles, compared to 19 of 34 (56%) on chromosome 17, and 17 of 33 (52%) on chromosome 18. Therefore, it appears that (i) FPC is a true dominant for adenomatosis but not a common recessive gene for colon cancer; and (ii) simple Mendelian models involving loss of alleles at a single locus may be inappropriate for understanding common human solid tumors.

Human villous adenomas engrafted into scid mice survive for prolonged period without malignant transformation.

Human villous adenomas are thought to represent premalignancies that subsequently give rise to colorectal adenocarcinomas. Currently there is no in vivo model in which to study the dedifferentiation and malignant transformation of these tumors. We establish here that human villous adenomas can be successfully engrafted into severe combined immunodeficient (scid) mice. Furthermore, these xenografts remain viable for up to 18 mo after either a subcutaneous or intraperitoneal inoculation of the human tissue. Tumors grew slowly and secreted a clear mucinous fluid. Examination of the tumors histologically at 1, 4, and 12 mo after implantation revealed that the villous polypoid structure was maintained and islands of atypical cells were observed within pockets of mucin surrounding the adenomatous tissue. No gross or histologic evidence of malignancy was detected throughout the 20-mo observation period. The human identity of the cells in the graft was confirmed by DNA in situ hybridization with a human-specific probe. We conclude that the human-scid xenograft described here represents a viable animal model with which to study the potential malignant dedifferentiation of villous adenomas over a prolonged period of time and to evaluate the possible contribution of selected oncogenic vectors on the malignant transformation of these adenomas.

p53 tumor suppressor gene status and the degree of genomic instability in sporadic colorectal cancers.

BACKGROUND: Genomic instability reflects the propensity and the susceptibility of the genome to acquire multiple alterations and, in turn, is believed to be a driving force behind multistep carcinogenesis. Although the molecular basis of genomic instability in sporadic colorectal cancers remains largely a mystery, mutation of the p53 tumor suppressor gene (also known as TP53) has been proposed to play an integral role in this process. However, a dilemma exists in that p53 mutation appears to be a late event in the progression of sporadic colorectal tumors, whereas genomic instability, serving as a facilitator of tumor progression, is envisioned as occurring early in this process. PURPOSE: We evaluated the relationship between p53 mutation and the major form of genomic instability in sporadic colorectal tumors, namely, that involving DNA breakage, which leads to chromosomal translocations, insertions, deletions, and gene amplification. METHODS: Fifty-eight sporadic colorectal tumors that had been previously evaluated for genomic instability were analyzed for p53 mutations. These tumors were from consecutively diagnosed patients. Genomic instability was quantified by use of inter-simple sequence repeat polymerase chain reaction analysis that employed (CA)8RG and (CA)8RY primers (R = purine [A or G]; Y = pyrimidine [C or T]); a genomic instability index (a measure of the number of alterations in tumor DNA in comparison with normal DNA, expressed as a percent) was calculated for each tumor. Mutation of the p53 gene in exons 5-9 was determined by use of single-strand conformational polymorphism-polymerase chain reaction analysis and DNA sequencing. Chi-squared analysis was used to determine the statistical significance of differences between groups of tumors. Reported P values are two-sided. RESULTS: p53 mutations were identified in 29 (50%) of the 58 tumors. The median genomic instability index value was 3.3%. Nineteen (65.5%) of the 29 tumors with p53 mutations had genomic instability indices that were less than the median value (range, 0%-2.6%); the remaining 10 (34.5%) tumors had genomic instability indices that were greater than the median (range, 3.9%-13.0%). Eleven (37.9%) of the 29 tumors with wild-type p53 genes had genomic instability indices that were less than the median value (range, 0%-2.6%), whereas the remaining 18 tumors had genomic instability indices above the median (range, 3.9%-11.7%). There was a statistically significant association between a lesser degree of genomic instability and the presence of p53 mutations (P = .032). CONCLUSIONS AND IMPLICATIONS: Tumors with no or minimal evidence of genomic instability are more likely to harbor p53 mutations than tumors with evidence of substantial genomic instability. p53 mutations play an important role in the development of cancers but do not appear to initiate or promote genomic instability in sporadic colorectal tumors.

Randomized trial of postoperative adjuvant chemotherapy with or without radiotherapy for carcinoma of the rectum: National Surgical Adjuvant Breast and Bowel Project Protocol R-02.

BACKGROUND: The conviction that postoperative radiotherapy and chemotherapy represent an acceptable standard of care for patients with Dukes' B (stage II) and Dukes' C (stage III) carcinoma of the rectum evolved in the absence of data from clinical trials designed to determine whether the addition of radiotherapy results in improved disease-free survival and overall survival. This study was carried out to address this issue. An additional aim was to determine whether leucovorin (LV)-modulated 5-fluorouracil (5-FU) is superior to the combination of 5-FU, semustine, and vincristine (MOF) in men. PATIENTS AND METHODS: Eligible patients (n = 694) with Dukes' B or C carcinoma of the rectum were enrolled in National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol R-02 from September 1987 through December 1992 and were followed. They were randomly assigned to receive either postoperative adjuvant chemotherapy alone (n = 348) or chemotherapy with postoperative radiotherapy (n = 346). All female patients (n = 287) received 5-FU plus LV chemotherapy; male patients received either MOF (n = 207) or 5-FU plus LV (n = 200). Primary analyses were carried out by use of a stratified log-rank statistic; P values are two-sided. RESULTS: The average time on study for surviving patients is 93 months as of September 30, 1998. Postoperative radiotherapy resulted in no beneficial effect on disease-free survival (P =.90) or overall survival (P =.89), regardless of which chemotherapy was utilized, although it reduced the cumulative incidence of locoregional relapse from 13% to 8% at 5-year follow-up (P =.02). Male patients who received 5-FU plus LV demonstrated a statistically significant benefit in disease-free survival at 5 years compared with those who received MOF (55% versus 47%; P =.009) but not in 5-year overall survival (65% versus 62%; P =.17). CONCLUSIONS: The addition of postoperative radiation therapy to chemotherapy in Dukes' B and C rectal cancer did not alter the subsequent incidence of distant disease, although there was a reduction in locoregional relapse when compared with chemotherapy alone.

An anoxia inducible endonuclease and enhanced DNA breakage as contributors to genomic instability in cancer.

Fischer rat embryo fibroblasts subjected to temporary anoxia followed by an aerobic recovery period show genomic instability in the form of highly elevated CAD gene amplification rates. As revealed by flow cytometric analysis this is associated with DNA breakage in vivo, followed by repair during the recovery period. Such genomic instability parallels expression of a M(r) 29,000/31,000 endonuclease; this enzyme requires no added divalent metal ion and has a pH optimum of about 6.5. The same endonuclease was found to be expressed within healing wounds and in four of ten human colorectal cancers but was not seen in eight normal colorectal tissue samples. Our results indicate that DNA breakage resulting from endogenous endonuclease activity can have a substantial effect in modulating genomic instability.

Enhanced levels of insulin-like growth factor messenger RNA in human colon carcinomas and liposarcomas.

The insulin-like growth factors I and II (IGF-I and -II) are proteins which stimulate cell proliferation and are important in normal human growth and development. They are coded for by separate genes and bind to specific cell surface receptors, eliciting a mitogenic response. IGFs are secreted by several cell lines derived from adult tumors. We have examined a number of human adult tumors for IGF messenger RNA (mRNA) expression and found IGF-II mRNA levels were consistently elevated in two types, colon carcinoma and liposarcoma. Adult colonic mucosa contains low levels of IGF-I and -II mRNA while several colon tumors, particularly of rectal and rectosigmoid origin, contained significantly elevated levels of IGF-II message. Over 90% of liposarcomas examined contained greatly elevated levels of IGF-II mRNA while control tissue (adipose) contained very low or undetectable IGF mRNA levels. Many of these tumors also contained elevated IGF-I mRNA levels. Northern analysis of these RNAs revealed differences in the abundance and sizes of IGF transcripts compared to other normal and malignant tissues known to express IGF.

Genomic DNA-based hMSH2 and hMLH1 mutation screening in 32 Eastern United States hereditary nonpolyposis colorectal cancer pedigrees.

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant cancer syndrome characterized by early age of onset colorectal cancer (mean 45 years) as well as endometrial, urinary tract, and upper gastrointestinal adenocarcinomas. The HNPCC phenotype has been shown to segregate with germline mutations in the human homologues of the DNA mismatch repair genes MSH2, MLH1, PMS1, and PMS2. However, the majority of published DNA mismatch repair gene mutation surveys associated with HNPCC kindreds report multiple levels of preselection, including 2p and 3p chromosomal linkage analysis and the evaluation of microsatellite instability of proband colorectal cancers prior to mutation analysis. For this reason, the concise contribution of each of the known DNA mismatch repair genes to the HNPCC phenotype remains unknown. We report the results of a genomic DNA-based analysis of hMSH2 and hMLH1 germline mutations in 32 unrelated Eastern United States HNPCC kindreds. These families were selected for study on the basis of phenotype only. We identified three hMSH2 and six hMLH1 mutations in eight families, for a positive mutation rate of 25%. Two mutations were identified in one of the families. Four of the mutations detected have not been reported in the literature previously. One of the mutation-positive families is African American; the others were of European-American ancestry. These results provide a clarification of the contribution of hMSH2 and hMLH1 to the HNPCC phenotype and suggest that in the majority of Eastern United States HNPCC kindreds selected by phenotype alone, the molecular genetic basis for the disease remains unknown.

Intrachromosomal genomic instability in human sporadic colorectal cancer measured by genome-wide allelotyping and inter-(simple sequence repeat) PCR.

We have used genome-wide allelotyping with 348 polymorphic autosomal markers spaced, on average, 10 cM apart to quantitate the extent of intrachromosomal instability in 59 human sporadic colorectal carcinomas. We have compared instability measured by this method with that measured by inter-(simple sequence repeat) PCR and microsatellite instability assays. Instability quantitated by fractional allelic loss rates was found to be independent of that detected by microsatellite instability analyses but was weakly associated with that measured by inter-(simple sequence repeat) PCR. A set of seven loci were identified that were most strongly associated with elevated rates of fractional allelic loss and/or inter-(simple sequence repeat) PCR instability; these seven loci were on chromosomes 3, 8, 11, 13, 14, 18, and 20. A lesser association was seen with two loci flanking p53 on chromosome 17. Coordinate loss patterns for these loci suggest that at least two separate sets of cooperating loci exist for intrachromosomal genomic instability in human colorectal cancer.

Plasma and tumor tissue pharmacology of high-dose intravenous leucovorin calcium in combination with fluorouracil in patients with advanced colorectal carcinoma.

Plasma pharmacokinetics of high-dose (500 mg/m2) leucovorin calcium (dl-5-formyltetrahydrofolic acid [dl-CF]) and fluorouracil (FUra) have been evaluated in patients with advanced colorectal cancer treated with the combination of FUra and dl-CF by two different intravenous (IV) schedules: (A) In patients with no prior chemotherapy, dl-CF was administered by a two-hour IV infusion and FUra by rapid IV injection one hour after the start of the dl-CF infusion and (B) in previously treated patients, dl-CF and FUra were administered by five-day continuous IV infusion (CI). Following the two-hour infusion of dl-CF, mean peak plasma concentration and elimination half-life of I-5-formyltetrahydrofolic acid (I-CF) were 24 +/- 6 mumol/L and 0.8 +/- 0.1 hour, respectively. CI of dl-CF over five days yielded a mean steady-state plasma level of I-CF of only 1.2 +/- 0.5 mumol/L. Peak and steady-state plasma concentrations of the metabolite 5-methyl tetrahydrofolic acid were comparable in the two schedules (17 +/- 8 mumol/L for the two-hour infusion and 12 +/- 5 mumol/L for the CI). Areas under the concentration v time curve (AUC) of total reduced folates were significantly greater under conditions of CI: 89.0 v 16.7 mmol/L/min for the two-hour infusion. In tumor tissue, 5,10-methylenetetrahydrofolate increased eight-fold two to four hours following the two-hour infusion and two-fold during the CI of dl-CF and FUra. Inhibition of thymidylate synthase (dTMP-S) by the two-hour and CI infusion schedules were 66% v 39%, respectively. The observed differences in the intracellular dTMP-S folate cofactor pools and the degree of inhibition of dTMP-S achieved in patients treated by two different schedules may be due to differences in the biochemical properties and/or to differences in the modulation of FUra metabolism by folate of tumor tissues obtained from newly diagnosed and previously treated patients.

Squamous cell carcinoma antigen as a marker for squamous cell carcinoma of the anal canal.

Twenty-one patients with documented squamous cell carcinoma (SCC) of the anal canal underwent prospective serial collection of 101 serum samples for radioimmunoassay of SCC antigen to evaluate regression or progression of disease. Eighteen presented with primary SCC of the anal canal, two with metastatic disease, and one with a recurrence in the perineum. Median follow-up was 18 months. Thirteen of 22 serum samples were true-positives, and nine of 22 were false-negatives. Four of 79 serum samples were false-positives and 75 of 79 were true-negatives. The sensitivity of this test is 59% and the specificity is 95%, with the accuracy of a positive test being 76%.

The benefit of leucovorin-modulated fluorouracil as postoperative adjuvant therapy for primary colon cancer: results from National Surgical Adjuvant Breast and Bowel Project protocol C-03.

PURPOSE: This study was designed to evaluate the efficacy of leucovorin-modulated fluorouracil (5-FU) as adjuvant therapy for patients with Dukes' stage B and C colon cancer. PATIENTS AND METHODS: Data are presented from 1,081 patients with Dukes' stage B and C carcinoma of the colon entered into National Surgical Adjuvant Breast and Bowel Project (NSABP) protocol C-03 between August 1987 and April 1989. Patients were randomly assigned to receive either lomustine (MeCCNU), vincristine, and 5-FU (MOF), or leucovorin-modulated 5-FU (LV + 5-FU). The mean time on study was 47.6 months. RESULTS: Comparison between the two groups indicates a disease-free survival advantage for patients treated with LV + 5-FU (P = .0004). The 3-year disease-free survival rate for patients in this group was 73% (95% confidence interval, 69% to 77%), compared with 64% (95% confidence interval, 60% to 68%) for patients receiving MOF. The corresponding percentage of patients surviving was 84% for those randomized to receive LV + 5-FU and 77% for the MOF-treated cohort (P = .003). At 3 years of follow-up, patients treated with postoperative LV + 5-FU had a 30% reduction in the risk of developing a treatment failure and a 32% reduction in mortality risk compared with similar patients treated with MOF. CONCLUSION: Treatment with LV + 5-FU significantly prolongs disease-free survival and results in a significant benefit relative to overall survival. These findings, when considered together with results from a recent meta-analysis demonstrating a benefit from LV + 5-FU in advanced disease, provide evidence to support the concept of metabolic modulation of 5-FU.

Randomized, placebo-controlled, multicenter trial of granulocyte-macrophage colony-stimulating factor as infection prophylaxis in oncologic surgery. Leukine Surgical Prophylaxis Research Group.

PURPOSE: Postoperative infections are a frequent source of preventable morbidity and mortality in the oncologic population. Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a potent modulator of immune effector cells in vitro and in vivo. This study was conducted to determine whether GM-CSF, when administered perioperatively, could reduce the incidence of surgical infections in cancer patients. METHODS: This was a prospective, randomized, placebo-controlled, multicenter study. Cancer patients at high risk of infectious surgical morbidity were randomized to receive GM-CSF 125 microg/m2 per day or placebo subcutaneously for 8 days beginning 3 days preoperatively. Routine antibiotic prophylaxis was administered to all patients. RESULTS: Three hundred ninety-nine patients were enrolled, with 198 randomized to receive GM-CSF. Twenty-one percent of patients experienced infections during the first 2 weeks postoperatively, and there was no difference in infection rate between the study groups. The most common sites of infection were respiratory tract (53%) and surgical wound (25%). The duration of operation and American Society of Anesthesiology (ASA) physical status classification were the most significant predictors of infection in multivariate analysis. GM-CSF was well tolerated and was not associated with fever. CONCLUSION: The eligibility criteria for this study were successful at defining a patient subgroup at high risk for postoperative infections. At an immunomodulatory dose of 125 microg/m2 per day, GM-CSF was safe and well tolerated, but did not reduce the incidence of postoperative infections in this high-risk oncologic population. Infectious morbidity in surgical oncology remains an important subject for continued clinical investigation.

Clinical utility of external immunoscintigraphy with the IMMU-4 technetium-99m Fab' antibody fragment in patients undergoing surgery for carcinoma of the colon and rectum: results of a pivotal, phase III trial. The Immunomedics Study Group.

PURPOSE: To assess the performance and the potential clinical impact of a new antibody imaging agent, CEA-Scan (Immunomedics Inc, Morris Plains, NJ), in 210 presurgical patients with advanced recurrent or metastatic colorectal carcinomas. METHODS: CEA-Scan, an anti-carcinoembryonic antigen (CEA) Fab antibody fragment labeled with technetium-99m-pertechnetate (99mTc), was injected intravenously (IV), and external scintigraphy was performed 2 to 5 and 18 to 24 hours later. Imaging with conventional diagnostic modalities (CDM) was also performed, and findings were confirmed by surgery and histology. RESULTS: The sensitivity of CEA-Scan was superior to that of CDM in the extrahepatic abdomen (55% v 32%; P = .007) and pelvis (69% v 48%; P = .005), and CEA-Scan findings complemented those of CDM in the liver. Among 122 patients with known disease, the positive predictive value was significantly higher when both modalities were positive (98%) compared with each alone (68% to 70%), potentially obviating the need for histologic confirmation when both tests are positive. Imaging accuracy also was significantly improved by adding CEA-Scan to CDM. In 88 patients with occult cancer, imaging accuracy was enhanced significantly by CEA-Scan combined with CDM (61% v 33%). Potential clinical benefit from CEA-Scan was demonstrated in 89 of 210 patients. Only two patients developed human antimouse antibodies (HAMA) to CEA-Scan after a single injection, and none of 19 assessable patients after two injections. CONCLUSION: CEA-Scan affords high-quality, same-day imaging, uses an inexpensive and readily available radio-nuclide, adds clinically significant information in assessing extent and location of disease in colorectal cancer patients, and only rarely induces a HAMA response.

Recommended colorectal cancer surveillance guidelines by the American Society of Clinical Oncology.

OBJECTIVE: To determine the most effective, evidence-based, postoperative surveillance strategy for the detection of recurrent colon and rectal cancer. Tests are to be recommended only if they have an impact on the outcomes listed below. POTENTIAL INTERVENTION: All tests described in the literature for postoperative monitoring were considered. In addition, the data were critically evaluated to determine the optimal frequency of monitoring. OUTCOMES: Outcomes of interest included overall and disease-free survival, quality of life, toxicity reduction, and cost-effectiveness. The American Society of Clinical Oncology (ASCO) Colorectal Cancer Surveillance Expert Panel was guided by the principle of cost minimization, ie, when two strategies were believed to be equally effective, the least expensive test was recommended. EVIDENCE: A complete MEDLINE search was performed of the past 20 years of the medical literature. Keywords included colorectal cancer, follow-up, and carcinoembryonic antigen, as well as the names of the specific tests. The search was broadened by articles from the tumor marker ASCO panel literature search, as well as from bibliographies of selected articles. VALUES: Levels of evidence and guideline grades were rated by a standard process. More weight was given to studies that tested a hypothesis directly relating testing to one of the primary outcomes in a randomized design. BENEFITS/HARMS/COSTS: The possible consequences of false-positive and false-negative tests were considered in evaluating a preference for one of two tests that provide similar information. Cost alone was not a determining factor. RECOMMENDATIONS: The expert panel's recommended postoperative monitoring schema is discussed in this article. VALIDATION: Five outside reviewers, the ASCO Health Services Research Committee, and the ASCO Board of Directors examined this document. SPONSOR: American Society of Clinical Oncology.

Evaluation of alpha-difluoromethylornithine as a potential chemopreventive agent: tolerance to daily oral administration in humans.

An initial clinical trial of alpha-difluoromethylornithine given p.o. daily for 6 months was carried out in 27 subjects free of disease following surgery for malignancy or in a defined high-risk group for cancer. The aim was to determine the highest nontoxic dose, principal side effects, and pharmacokinetic parameters. The starting dose was 200 mg/m2/day in divided doses with escalation each month in the absence of toxicity to 6400 mg/m2/day or to the highest nontoxic dose, whichever was lower. When the highest nontoxic dose was reached, this dose was continued to complete 26 weeks of treatment. Twenty-two subjects completed 26 weeks of alpha-difluoromethylornithine treatment of whom 20 reached a nontoxic dose of at least 1600 mg/m2/day. The dose-limiting toxicity was loss of high-tone auditory acuity on an audiogram. Other side effects included diarrhea, fatigue, joint pain, insomnia, and rash. Pharmacokinetics were linear with dose. Area under the plasma concentration x time curve and maximum plasma concentration of alpha-difluoromethylornithine did not predict for development of ototoxicity. The dose for phase II chemoprevention studies should not exceed 1600 mg/m2/day.

Familial and nutritional risk factors for p53 overexpression in colorectal cancer.

Although familial and dietary factors are recognized as important risk determinants for colorectal tumorigenesis, the specific causes of colorectal cancer remain unclear. Studies of p53 genetic alterations have provided clues concerning the etiology of many cancers. This study was designed to determine whether overexpression of the p53 protein is associated with familial and dietary risk factors. Epidemiological data were obtained from 163 colorectal cancer cases and 326 healthy controls. Tumors of all patients were analyzed immunohistochemically for p53 overexpression using an avidin-biotin immunoperoxidase procedure and polyclonal anti-p53 antibody CM1. Of patient tumors, 44.8% showed p53 nuclear reactivity. Colorectal cases versus controls were three times more likely to report a family history of colorectal cancer [odds ratio (OR), 3.12; 95% confidence interval (CI), 1.77-5.52]. Only cruciferous vegetables exhibited a significant inverse association (OR, 0.59; 95% CI, 0.34-1.02; trend test, P = 0.03) for the highest versus lowest quartiles. Both meat and beef displayed an elevated increase in risk. When cases with p53 overexpression (p53 positive) were compared with cases without p53 overexpression (p53 negative), etiological heterogeneity was suggested for family history of colorectal cancer (OR, 0.39; 95% CI, 0.16-0.93), cruciferous vegetables (trend test, P = 0.12), and beef consumption (trend test, P = 0.08). To estimate the individual relative risks for p53-dependent and p53-independent pathways, each p53 subtype was compared with controls. Cruciferous vegetables exhibited a significant association (OR, 0.37; 95% CI, 0.17-0.82; trend test, P = 0.03) when p53 positive cases were compared with controls. When p53 negative cases were compared with controls, a significant increase in risk was observed for family history of cancer (OR, 4.46; 95% CI, 2.36-8.43) and beef (OR, 3.17; 95% CI, 1.83-11.28; trend test, P = 0.006). The p53 (positive) dependent pathway was characterized by an inverse association with cruciferous vegetables, and p53-independent tumors were characterized by family history and beef consumption. These data may indicate the significance of linking epidemiology and molecular biology in assessing specific etiological pathways.

High prevalence of Inoue-Melnick virus antibodies in patients with colorectal carcinoma.

The high prevalence of serum neutralizing antibodies against Inoue-Melnick virus (IMV) among American patients with colorectal carcinoma has been confirmed. Sera from 26 patients with colorectal carcinoma along with the identical number of age- and sex-matched patients with non-colorectal neoplasia and normal healthy controls were collected in the Buffalo area. All of the colorectal carcinoma group possessed antibodies against IMV (100%), while antibody positivity for non-colorectal neoplasia and for normal controls were 34.6% and 38.5%, respectively. Geometric mean titers of antibodies to IMV type 1 and type 2 for colorectal carcinoma were 266 and 338, respectively, whereas the mean titers in the other two control groups were less than 10.3. These differences between colorectal carcinoma and the two controls were highly significant (P less than 0.001). The majority of patients with colorectal carcinoma had antibodies to both IMV types 1 and 2.

D-14 monoclonal antibody to carcinoembryonic antigen: immunohistochemical analysis of formalin-fixed, paraffin-embedded human colorectal carcinoma, tumors of non-colorectal origin and normal tissues.

The reactivity of D-14 monoclonal antibody (mAb) to a specific epitope of carcinoembryonic antigen (CEA) was evaluated on formalin-fixed, paraffin-embedded tissues. A total of 52 normal tissues, 90 colorectal carcinomas and 127 non-colorectal neoplasms were tested using the peroxidase/antiperoxidase technique. D-14 mAb did not react with normal tissues apart from producing a weak staining of normal colonic glands immediately adjacent to the neoplastic structures. All 61 primary and 29 metastatic colorectal carcinomas expressed the carcinoembryonic antigen. However, there was considerable heterogeneity in cellular antigen expression in both primary and metastatic colorectal carcinomas with 10%-99% of tumor cells staining. Of 22 stomach adenocarcinomas, 14 were also immunoreactive, as were 2 of 5 pancreatic carcinomas. Only 6 of 100 neoplasms of non-gastrointestinal origin expressed weak to moderate immunoreactivity. In 7 cases, colorectal micrometastases not recognized in conventional hematoxylin and eosin slides could be identified with D-14 mAb. The specificity of this antibody could be used in differentiating colorectal carcinomas from other types of tumors, including adenocarcinoma from other sites.

Primary adenocarcinoma arising in an ileostomy.

Two cases are added to the world literature of patients in whom an adenocarcinoma developed at the ileostomy site after total proctocolectomy for ulcerative colitis. Fourteen additional cases have been reported in the world literature; of these, 12 cases have been in patients with ulcerative colitis, and four cases have been in patients with familial adenomatous polyposis. Adenocarcinoma of an ileostomy is not common. However, in the analysis of the reported cases, patients with long-standing ileostomies appear to be at a greater risk. With an aging ileostomy population, an increase in the number of cases may be seen. Three hypotheses are discussed as potential causative pathways to this entity. Continued analysis of these cases may yield information on the pathophysiology involved.