U-CAN: a prospective longitudinal collection of biomaterials and clinical information from adult cancer patients in Sweden.

BACKGROUND: Progress in cancer biomarker discovery is dependent on access to high-quality biological materials and high-resolution clinical data from the same cases. To overcome current limitations, a systematic prospective longitudinal sampling of multidisciplinary clinical data, blood and tissue from cancer patients was therefore initiated in 2010 by Uppsala and Umeå Universities and involving their corresponding University Hospitals, which are referral centers for one third of the Swedish population. MATERIAL AND METHODS: Patients with cancer of selected types who are treated at one of the participating hospitals are eligible for inclusion. The healthcare-integrated sampling scheme encompasses clinical data, questionnaires, blood, fresh frozen and formalin-fixed paraffin-embedded tissue specimens, diagnostic slides and radiology bioimaging data. RESULTS: In this ongoing effort, 12,265 patients with brain tumors, breast cancers, colorectal cancers, gynecological cancers, hematological malignancies, lung cancers, neuroendocrine tumors or prostate cancers have been included until the end of 2016. From the 6914 patients included during the first five years, 98% were sampled for blood at diagnosis, 83% had paraffin-embedded and 58% had fresh frozen tissues collected. For Uppsala County, 55% of all cancer patients were included in the cohort. CONCLUSIONS: Close collaboration between participating hospitals and universities enabled prospective, longitudinal biobanking of blood and tissues and collection of multidisciplinary clinical data from cancer patients in the U-CAN cohort. Here, we summarize the first five years of operations, present U-CAN as a highly valuable cohort that will contribute to enhanced cancer research and describe the procedures to access samples and data.

Telomere length in peripheral leukocytes is associated with immune cell tumor infiltration and prognosis in colorectal cancer patients.

Telomeres are protective structures at the end of chromosomes, essential for chromosomal integrity. A large number of studies have investigated leukocyte telomere length as a possible risk marker for various cancers, colorectal cancer (CRC) included. In contrast, studies investigating leukocyte telomere length in relation to CRC survival are lacking. We previously reported that relative telomere length (RTL) of leukocytes collected at diagnosis predicted survival in patients with breast and kidney cancer. We suggested that these findings might reflect various immunological mechanisms, affected by the presence of a tumor. In the present study, leukocyte RTL was examined in relation to immune cell tumor infiltration and prognosis in 130 patients with CRC diagnosis. RTL was measured with a well-established qPCR method. We found that patients with the highest degree of lymphocyte tumor infiltration had shorter leukocyte RTL. Consistent with our previous findings, short RTL was a favorable prognostic marker in univariate survival analysis. In the current study, RTL did not remain as an independent predictor in multivariate survival analysis, when including metastatic status in the model. However, a non-significant trend towards a similar telomere-associated survival pattern was observed in patients with limited disease. In contrast, for patients who died of other causes than CRC, short RTL was associated with significantly shorter survival time. To our knowledge, this is the first study to investigate an association between leukocyte RTL, immune cell tumor infiltration, and cancer-specific survival in CRC patients. Larger studies are warranted to verify these findings.

High intratumoral expression of fibroblast activation protein (FAP) in colon cancer is associated with poorer patient prognosis.

An active stroma is important for cancer cell invasion and metastasis. We investigated the expression of fibroblast activation protein (FAP) in relation to patient prognosis in colorectal cancer. Colorectal cancer specimens from 449 patients were immunohistochemically stained with a FAP antibody and evaluated in the tumor center and tumor front using a semiquantitative four-level scale. FAP was expressed by fibroblasts in 85-90 % of the tumors examined. High versus no/low expression in the tumor center was associated with poor prognosis (multivariate hazard ratio, HR = 1.72; 95 % CI 1.07-2.77, p = 0.025). FAP expression in the tumor front, though more frequent than in the tumor center, was not associated with prognosis. FAP expression in the tumor center was more common in specimens with positive microsatellite instability (MSI) screening status and in patients with high CpG island methylator phenotype (CIMP) status. However, inclusion of MSI screening status and CIMP status in the multivariate analysis strengthened the risk estimates for high FAP expression in the tumor center (HR = 1.89; 95 % CI 1.13-3.14; p = 0.014), emphasizing the role of FAP as an independent prognostic factor. Stromal FAP expression is common in colorectal cancer, and we conclude that high FAP expression in the tumor center, but not the tumor front, is an independent negative prognostic factor.

Genetic variation in alcohol dehydrogenase (ADH1A, ADH1B, ADH1C, ADH7) and aldehyde dehydrogenase (ALDH2), alcohol consumption and gastric cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.

Studies that have examined the association between alcohol consumption and gastric cancer (GC) risk have been inconsistent. We conducted an investigation of 29 genetic variants in alcohol metabolism loci (alcohol dehydrogenase, ADH1 gene cluster: ADH1A, ADH1B and ADH1C; ADH7 and aldehyde dehydrogenase, ALDH2), alcohol intake and GC risk. We analyzed data from a nested case-control study (364 cases and 1272 controls) within the European Prospective Investigation into Cancer and Nutrition cohort. Single nucleotide polymorphisms (SNPs) were genotyped using a customized array. We observed a statistically significant association between a common 3'-flanking SNP near ADH1A (rs1230025) and GC risk [allelic odds ratio (OR)(A v T) = 1.30, 95% confidence interval (CI) = 1.07-1.59]. Two intronic variants, one in ADH1C (rs283411) and one in ALDH2 (rs16941667), also were associated with GC risk (OR(T v C) = 0.59; 95% CI = 0.38-0.91 and OR(T v C) = 1.34; 95% CI = 1.00-1.79, respectively). Individuals carrying variant alleles at both ADH1 (rs1230025) and ALDH2 (rs16941667) were twice as likely to develop GC (OR(A+T) = 2.0; 95% CI = 1.25-3.20) as those not carrying variant alleles. The association between rs1230025 and GC was modified by alcohol intake (<5 g/day: OR(A) = 0.89, 95% CI = 0.57-1.39; ≥5 g/day: OR(A) = 1.45, 95% CI = 1.08-1.94, P-value = 0.05). The association was also modified by ethanol intake from beer. A known functional SNP in ADH1B (rs1229984) was associated with alcohol intake (P-value = 0.04) but not GC risk. Variants in ADH7 were not associated with alcohol intake or GC risk. In conclusion, genetic variants at ADH1 and ALDH2 loci may influence GC risk, and alcohol intake may further modify the effect of ADH1 rs1230025. Additional population-based studies are needed to confirm our results.

Prostate stem-cell antigen gene is associated with diffuse and intestinal gastric cancer in Caucasians: results from the EPIC-EURGAST study.

A genome-wide study performed in a Japanese population identified a strong association between SNP rs2294008 (Met1Thr) in the Prostate Stem Cell Antigen gene (PSCA) and diffuse-type gastric cancer (GC). This association was validated in different Asian populations, and, very recently, a study has been published in Caucasians. In this study, we analyzed the association between PSCA variation and GC risk in Caucasians from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Six tagSNPs covering the PSCA gene region were genotyped in 411 incident gastric adenocarcinoma cases and 1530 matched controls from a nested case-control study in the EPIC cohort. Associations were analyzed by unconditional logistic regression, adjusting for age, sex and country. The T allele of rs2294008 in PSCA was found to be a highly significant risk factor for GC (per allele OR = 1.42, 95% CI: 1.23-1.66, p-value = 6.5 × 10(-6) ), particularly of the noncardia-type (per allele OR = 1.47, 95% CI: 1.19-1.81, p-value = 3 × 10(-4) ). At contrast with previous studies, no significant differences were observed between the diffuse (per allele OR = 1.54, 95% CI: 1.20-1.96, p-value = 5 × 10(-4) ) and the intestinal (per allele OR = 1.52, 95% CI: 1.20-1.93, p-value = 5 × 10(-4) ) GC histological subtypes. Although rs12155758 and rs9297976 were also found associated with GC, this association appeared to be due to linkage disequilibrium with rs2294008. Haplotype analysis did not provide additional information. These results confirm the association between variation in the promoter region of PSCA and GC risk in Caucasians and also indicate that the rs2294008 variant is a similar risk factor for both the diffuse and intestinal-types of GC.

Dietary intake of heme iron and risk of gastric cancer in the European prospective investigation into cancer and nutrition study.

Even though recent studies suggest that a high intake of heme iron is associated with several types of cancer, epidemiological studies in relation to gastric cancer (GC) are lacking. Our previous results show a positive association between red and processed meat and non cardia gastric cancer, especially in Helicobacter pylori infected subjects. The aim of the study is to investigate the association between heme iron intake and GC risk in the European prospective investigation into cancer and nutrition (EURGAST-EPIC). Dietary intake was assessed by validated center-specific questionnaires. Heme iron was calculated as a type-specific percentage of the total iron content in meat intake, derived from the literature. Antibodies of H. pylori infection and vitamin C levels were measured in a sub-sample of cases and matched controls included in a nested case-control study within the cohort. The study included 481,419 individuals and 444 incident cases of GC that occurred during an average of 8.7 years of followup. We observed a statistically significant association between heme iron intake and GC risk (HR 1.13 95% CI: 1.01-1.26 for a doubling of intake) adjusted by sex, age, BMI, education level, tobacco smoking and energy intake. The positive association between heme iron and the risk of GC was statistically significant in subjects with plasma vitamin C <39 mmol/l only (log2 HR 1.54 95% CI (1.01-2.35). We found a positive association between heme iron intake and gastric cancer risk.

Dietary total antioxidant capacity and gastric cancer risk in the European prospective investigation into cancer and nutrition study.

A high intake of dietary antioxidant compounds has been hypothesized to be an appropriate strategy to reduce gastric cancer (GC) development. We investigated the effect of dietary total antioxidant capacity (TAC) in relation to GC in the European Prospective Investigation into Cancer (EPIC) study including 23 centers in 10 European countries. A total of 521,457 subjects (153,447 men) aged mostly 35-70 years old, were recruited largely between 1992 and 1998. Ferric reducing antioxidant potential (FRAP) and total radical-trapping antioxidant parameter (TRAP), measuring reducing and chain-breaking antioxidant capacity were used to measure dietary TAC from plant foods. Dietary antioxidant intake is associated with a reduction in the risk of GC for both FRAP (adjusted HR 0.66; 95%CI (0.46-0.95) and TRAP (adjusted HR 0.61; 95%CI (0.43-0.87) (highest vs. lowest quintile). The association was observed for both cardia and noncardia cancers. A clear effect was observed in smokers with a significant reduction in GC risk for the fifth quintile of intake for both assays (highest vs. lowest quintile: adjusted HR 0.41; 95%CI (0.22-0.76) p for trend <0.001 for FRAP; adjusted HR 0.52; 95%CI (0.28-0.97) p for trend <0.001 for TRAP) but not in nonsmokers. In former smokers, the association with FRAP intake was statistically significant (highest vs. lowest quintile: adjusted HR 0.4; 95%CI (0.21-0.75) p < 0.05); no association was observed for TRAP. Dietary antioxidant capacity intake from different sources of plant foods is associated with a reduction in the risk of GC.

Colorectal cancer cells activate adjacent fibroblasts resulting in FGF1/FGFR3 signaling and increased invasion.

Cancer-associated fibroblasts expressing fibroblast activation protein (FAP) have been implicated in the invasive behavior of colorectal cancer. In this study, we use FAP expression as a marker of fibroblast activation and analyze the effect of activated fibroblasts on colorectal cancer migration and invasion in experimental cell studies. We also investigated the expression pattern of FAP in cancer-associated fibroblasts during transformation from benign to malignant colorectal tumors. In immunohistochemical analyses, FAP was expressed in fibroblasts in all colorectal cancer samples examined, whereas all normal colon, hyperplastic polyps, or adenoma samples were negative. In in vitro studies, conditioned medium from colon cancer cells, but not adenoma cells, activated fibroblasts by inducing FAP expression. These activated fibroblasts increased the migration and invasion of colon cancer cells in Boyden chamber experiments and in a three-dimensional cell culture model. We identify fibroblast growth factor 1/fibroblast growth factor receptor 3 (FGF1/FGFR-3) signaling as mediators leading to the increased migration and invasion. Activated fibroblasts increase their expression of FGF1, and by adding a fibroblast growth factor receptor inhibitor, as well as an FGF1-neutralizing antibody, we reduced the migration of colon cancer cells. Our findings provide evidence of a possible molecular mechanism involved in the cross talk between cancer cells and fibroblasts leading to cancer cell invasion.

Colorectal cancer prognosis depends on T-cell infiltration and molecular characteristics of the tumor.

The aim of this study was to relate the density of tumor infiltrating T cells to cancer-specific survival in colorectal cancer, taking into consideration the CpG island methylator phenotype (CIMP) and microsatellite instability (MSI) screening status. The T-cell marker CD3 was stained by immunohistochemistry in 484 archival tumor tissue samples. T-cell density was semiquantitatively estimated and scored 1-4 in the tumor front and center (T cells in stroma), and intraepithelially (T cells infiltrating tumor cell nests). Total CD3 score was calculated as the sum of the three CD3 scores (range 3-12). MSI screening status was assessed by immunohistochemistry. CIMP status was determined by quantitative real-time PCR (MethyLight) using an eight-gene panel. We found that patients whose tumors were highly infiltrated by T cells (total CD3 score ≥7) had longer survival compared with patients with poorly infiltrated tumors (total CD3 score ≤4). This finding was statistically significant in multivariate analyses (multivariate hazard ratio, 0.57; 95% confidence interval, 0.31-1.00). Importantly, the finding was consistent in rectal cancer patients treated with preoperative radiotherapy. Although microsatellite unstable tumor patients are generally considered to have better prognosis, we found no difference in survival between microsatellite unstable and microsatellite stable (MSS) colorectal cancer patients with similar total CD3 scores. Patients with MSS tumors highly infiltrated by T cells had better prognosis compared with intermediately or poorly infiltrated microsatellite unstable tumors (log rank P=0.013). Regarding CIMP status, CIMP-low was associated with particularly poor prognosis in patients with poorly infiltrated tumors (multivariate hazard ratio for CIMP-low versus CIMP-negative, 3.07; 95% confidence interval, 1.53-6.15). However, some subset analyses suffered from low power and are in need of confirmation by independent studies. In conclusion, patients whose tumors are highly infiltrated by T cells have a beneficial prognosis, regardless of MSI, whereas the role of CIMP status in this context is less clear.

Menstrual and reproductive factors, exogenous hormone use, and gastric cancer risk in a cohort of women from the European Prospective Investigation Into Cancer and Nutrition.

The worldwide incidence of gastric adenocarcinoma (GC) is lower in women than in men. Furthermore, cancer patients treated with estrogens have been reported to have a lower subsequent risk of GC. The authors conducted a prospective analysis of menstrual and reproductive factors, exogenous hormone use, and GC in 335,216 women from the European Prospective Investigation Into Cancer and Nutrition, a cohort study of individuals aged 35-70 years from 10 European countries. After a mean follow-up of 8.7 years (through 2004), 181 women for whom complete exposure data were available developed GC. Adjusted hazard ratios and 95% confidence intervals were estimated using Cox proportional hazards models. All statistical tests were 2-sided. Women who had ovariectomy had a 79% increased risk of GC (based on 25 cases) compared with women who did not (hazard ratio = 1.79, 95% confidence interval: 1.15, 2.78). Total cumulative years of menstrual cycling was inversely associated with GC risk (fifth vs. first quintile: hazard ratio = 0.55, 95% confidence interval: 0.31, 0.98; P(trend) = 0.06). No other reproductive factors analyzed were associated with risk of GC. The results of this analysis provide some support for the hypothesis that endogenous ovarian sex hormones lower GC incidence in women.

Prospective study of physical activity and risk of primary adenocarcinomas of the oesophagus and stomach in the EPIC (European Prospective Investigation into Cancer and nutrition) cohort.

OBJECTIVE: To analyse the association between types of physical activity (occupational, recreational and household, vigorous and overall) and risk of primary oesophageal (OAC) or gastric adenocarcinoma (GAC). METHODS: From nine European countries, 420,449 participants were recruited between 1991 and 2000 and followed-up for a mean of 8.8 years to register incident GAC and OAC. Information on physical activity (PA), diet, lifestyle and health-related variables was obtained at baseline. Helicobacter pylori infection status was considered in a subset of 1,211 participants. Analyses were repeated by tumour site (cardia/non-cardia) and histological type (intestinal/diffuse). RESULTS: During the follow-up, 410 GAC and 80 OAC occurred. A lower risk of overall and non-cardia GAC was found for increasing levels of a PA index which combined occupational PA with weekly time spent in sports and cycling. The hazard ratio (HR) of GAC was 0.69, 95% CI: 0.50-0.94, for the comparison between active and inactive participants according to the PA index (HR = 0.44, 95% CI:0.26-0.74, for non-cardia GAC). No effect was found for cardia tumours or histological subtypes of GAC. PA of any kind was not associated with OAC. CONCLUSIONS: Overall and distal (non-cardia) gastric tumours were inversely associated with time spent on cycling and sports and a total PA index. No association was found for any type of PA and risk of cardia cancers of the stomach.

ErbB 1-4 expression alterations in primary colorectal cancers and their corresponding metastases.

BACKGROUND: EGFR (epidermal growth factor receptor) targeted therapies are important new tools in colorectal cancer treatment. EGFR analysis of the primary tumour was previously recommended to identify patients who will benefit from the EGFR targeted therapy. Previous studies have displayed diverging results regarding the expression of EGFR in the primary tumour compared to the metastases. The present study was performed to investigate whether EGFR and ErbB2-4 expression differed between 64 primary tumours and their corresponding metastases. PATIENTS AND METHODS: EGFR and ErbB2-4 expression were analysed in the primary tumour and in the corresponding metastases using immunohistochemistry (IHC). RESULTS: In 49/64 samples (76%), the primary tumours were EGFR positive; in 33% (16/49) of EGFR positive samples, the tumours lost the EGFR expression in the metastasis compared to the primary tumour. From the primary tumours, 15/64 (23%) were negative and 5 of these (33%) developed EGFR expression in the metastasis. ErbB2, ErbB3, and ErbB4 expression was evident in 54%, 67%, and 81%, respectively. There was no significant difference between ErbB2, ErbB3, and ErbB4 expression in primary tumours and metastases. The co-expression of the ErbB family members was also analysed, with a significant increase of ErbB3/ErbB4 co-expression in late stage tumours. CONCLUSION: The EGFR expression was lost in 33% of metastasising primary colorectal cancer tumours, a finding that agrees with at least one previous study. Thus, the present results clearly implicate the need for EGFR analysis of both the primary tumour and metastases to accurately determine EGFR status when considering the use of EGFR targeted therapies.

CDH1 gene polymorphisms, smoking, Helicobacter pylori infection and the risk of gastric cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC-EURGAST).

Despite declining incidence rates, gastric cancer (GC) is a major cause of death worldwide. E-Cadherin is an adhesion molecule that is thought to be involved in GC. Germline mutations in the E-Cadherin gene (CDH1) have been identified in hereditary diffuse GC. Also, a promoter polymorphism at position -160 C/A has been suggested to lead to transcriptional down regulation and has been shown to affect GC risk in some studies. However, very little information exists on the GC risk association of other CDH1 polymorphisms and it is unclear whether any associations may be different by GC anatomical sites or histological types. Thus, a case-control study (cases=245/controls=950) nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort was conducted to assess the GC risk association of eight CDH1 gene polymorphisms. None of the CDH1 polymorphisms or haplotypes analysed were associated with GC risk and no differences of effect were observed by Helicobacter pylori infection status. However, three CDH1 polymorphisms in the same haplotype block, including the CDH1-160C/A, interacted with smoking to increase GC risk in smokers but not in never smokers. These findings should be confirmed in larger independent studies.

High macrophage infiltration along the tumor front correlates with improved survival in colon cancer.

PURPOSE: The role of macrophages in tumorigenesis is complex because they can both prevent and promote tumor development. EXPERIMENTAL DESIGN: Four hundred forty-six colorectal cancer specimens were stained with the pan-monocyte/macrophage marker CD68, and average infiltration along the tumor front was semiquantitatively evaluated using a four-grade scale. Each section was similarly scored for the presence of CD68 hotspots. Some aspects of macrophage-tumor cell interactions were also studied using in vitro coculture systems. RESULTS: Including all patients, regardless of surgical outcome and localization, survival increased incrementally with CD68TF(Mean) infiltration grade (P = 0.0001) but not in curatively resected colon cancers (P = 0.28). CD68 hotspot score (CD68TF(Hotspot)) was divided into high and low. A high hotspot score conferred a highly significant survival advantage also in curatively resected colon cancer cases (n = 199, P = 0.0002) but not in rectal cancers. CD68TF(Hotspot) high turned out as an independent prognostic marker for colon cancer in multivariate analyses including gender, age, localization, grade, stage, tumor type, and lymphocytes at the tumor front, conferring a relative risk of 0.49 (P = 0.007). In vitro coculture experiments, using phorbol 12-myristate 13-acetate-activated U937 cells as macrophage model, revealed that a high ratio of macrophages to colon cancer cells inhibited cancer cell growth. This was partially dependent on cell-to-cell contact, whereas Boyden chamber cocultivation without cell-to-cell contact promoted cancer cell spread. CONCLUSIONS: In conclusion, our data indicate that a dense macrophage infiltration at the tumor front positively influences prognosis in colon cancer and that the degree of cell-to-cell contact may influence the balance between protumorigenic and antitumorigenic properties of macrophages.

Early onset of ulcerative colitis: long-term follow-up with special reference to colorectal cancer and primary sclerosing cholangitis.

OBJECTIVES: Ulcerative colitis (UC) is associated with an increased risk of colorectal cancer (CRC) and primary sclerosing cholangitis (PSC). The onset of UC at a young age has been considered a specific risk factor for CRC. This study reports the outcome with respect to DNA aneuploidy, dysplasia, CRC, and PSC in a cohort of patients with early-onset UC from a defined catchment area who were followed up for 45 years. PATIENTS AND METHODS: The study period was from 1961 through 2005. In all, 46 children and adolescents, ages 18 or younger from our catchment area, were affected with UC during this time. Data were collected from our colonoscopic surveillance program and other medical records in the same hospital. RESULTS: The incidence rate of UC was 1.6 children or adolescents per 100,000 inhabitants per year. The onset of disease was at age 14 years (mean and median), and the observed duration of disease was 0 to 44 years. Five patients died, 3 of them of intercurrent disease. CRC developed in 1 patient, and no death caused by this disease was observed. PSC was diagnosed in 4 patients, in all of whom the onset of UC occurred before age 15. CONCLUSIONS: The earlier reports of increased risk of CRC in patients with early-onset UC was not seen in this study. This could be due to a high frequency of surgery together with a well-functioning surveillance program with excellent compliance. The recommendation of surgery in cases of high-grade dysplasia or repeated findings of low-grade dysplasia seems to be effective in the attempt to minimize the risk for CRC. We observed a rather high incidence of PSC, which may indicate that more attention should be paid to a search for this diagnosis in patients with early-onset UC.

The association of gastric cancer risk with plasma folate, cobalamin, and methylenetetrahydrofolate reductase polymorphisms in the European Prospective Investigation into Cancer and Nutrition.

Previous studies have shown inconsistent associations of folate intake and polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene with gastric cancer risk. Our nested case-control study within the European Prospective Investigation into Cancer and Nutrition cohort is the first prospective study of blood folate levels and gastric cancer. Gastric cancer cases (n=247) and controls (n=631) were matched for study center, age, sex, and time of blood donation. Two common single nucleotide polymorphisms of the MTHFR gene were determined, as were plasma concentrations of folate, cobalamin (vitamin B12), total homocysteine, and methylmalonic acid (cobalamin deficiency marker) in prediagnostic plasma. Risk measures were calculated with conditional logistic regression. Although no relations were observed between plasma folate or total homocysteine concentrations and gastric cancer, we observed a trend toward lower risk of gastric cancer with increasing cobalamin concentrations (odds ratio, 0.79 per SD increase in cobalamin; P=0.01). Further analyses showed that the inverse association between cobalamin and gastric cancer was confined to cancer cases with low pepsinogen A levels (marker of severe chronic atrophic gastritis) at the time of blood sampling. The 677 C-->T MTHFR polymorphism was not associated with gastric cancer, but we observed an increased risk with the variant genotype of the 1298 A-->C polymorphism (odds ratio, 1.47 for CC versus AA; P=0.04). In conclusion, we found no evidence of a role of folate in gastric cancer etiology. However, we observed increased gastric cancer risk at low cobalamin levels that was most likely due to compromised cobalamin status in atrophic gastritis preceding gastric cancer.

Altered expression of CK7 and CK20 in preneoplastic and neoplastic lesions in ulcerative colitis.

This study is based on all patients with ulcerative colitis from a defined catchment area in Northern Sweden in a still ongoing colonoscopy surveillance programme, which started in 1977. From this material we selected tissue from eight groups of patients consisting of normal control biopsies (5), inactive colitis (10), active colitis (10), findings of low-grade dysplasia (10), high-grade dysplasia (6), aneuploidy (without dysplasia and with subsequent dysplasia) (10), and ulcerative colitis-associated cancers (5). The samples were evaluated according to immunohistochemical expression of CK7 and CK20. Colonic mucosa from normal controls and inactive colitis was found to be completely negative for CK7. In 9 out of 10 patients with active colitis, CK7 was sparsely expressed in a patchy manner and connected with active epithelial inflammatory areas. 7 out of 10 patients with low-grade dysplasia and 3 out of 6 with high-grade dysplasia were positive for CK7. Samples with aneuploidy without dysplasia were completely negative, while 2 out of 6 showing subsequent dysplasia were positive. Of the five cancers, two were positive for CK7. CK20 was expressed in nearly all samples but relatively more in the lower part of the crypts in neoplasia-associated lesions. Our results indicate a possible relationship between expression of CK7 and CK20 and neoplastic development of colorectal mucosa in patients with ulcerative colitis. Further studies are needed to elucidate whether these findings have clinical significance.

Socioeconomic position and the risk of gastric and oesophageal cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC-EURGAST).

OBJECTIVES: To evaluate the association of socioeconomic position with adenocarcinoma of the oesophagus and stomach. METHODS: The European Prospective Investigation into Cancer and Nutrition (EPIC) cohort comprises about 520 000 participants mostly aged 35-70 years. Information on diet and lifestyle was collected at recruitment. After an average follow-up of 6.5 years, 268 cases with adenocarcinoma of the stomach and 56 of the oesophagus were confirmed. We examined the effect of socioeconomic position on cancer risk by means of educational data and a computed Relative Index of Inequality (RII). In a nested case-control study, adjustment for Helicobacter pylori (H. pylori) infection was performed. RESULTS: Higher education was significantly associated with a reduced risk of gastric cancer [vs lowest level of education, hazard ratio (HR): 0.64, 95% Confidence intervals (CI): 0.43-0.98]. This effect was more pronounced for cancer of the cardia (HR: 0.42, 95% CI: 0.20-0.89) as compared to non-cardia gastric cancer (HR: 0.66, 95% CI: 0.36-1.22). Additionally, the inverse association of educational level and gastric cancer was stronger for cases with intestinal (extreme categories, HR: 0.13, 95% CI: 0.04-0.44) rather than diffuse histological subtype (extreme categories, HR: 0.71 95% CI: 0.37-1.40). In the nested case-control study, inverse but statistically non-significant associations were found after additional adjustment for H. pylori infection [highest vs lowest level of education: Odds ratio (OR) 0.53, 95% CI: 0.24-1.18]. Educational level was non-significantly, inversely associated with carcinoma of the oesophagus. CONCLUSION: A higher socioeconomic position was associated with a reduced risk of gastric adenocarcinoma, which was strongest for cardia cancer or intestinal histological subtype, suggesting different risk profiles according to educational level. These effects appear to be explained only partially by established risk factors.

Beta-catenin expression in relation to genetic instability and prognosis in colorectal cancer.

In the carcinogenesis of colorectal cancer (CRC) genetic instability and dysfunction of the Wnt-signalling pathway play important roles. Most Wnt-signalling dysfunctions lead to the nuclear accumulation of beta-catenin. The aim of the present study was to investigate whether nuclear accumulation of beta-catenin is associated with prognosis and genetic instability. We used immunohistochemistry to study nuclear beta-catenin expression in 67 CRCs. The expression was evaluated in the entire tumour section as mean values and in tumour budding at the invasive margin. We compared the results with chromosomal and microsatellite instability (CIN vs. MSI), p53 accumulation, and clinicopathological variables including survival. The nuclear accumulation of beta-catenin was significantly associated with abnormal p53 expression and aneuploidy, typically for CIN, whereas no tumour with nuclear beta-catenin expression at the invasive margin displayed MSI. The beta-catenin expression pattern did not correlate significantly with CRC patient prognosis when including all stages. However, in the clinically most interesting prognostic group, Dukes' stage B patients, high nuclear accumulation of beta-catenin was associated with a poor prognosis (p=0.01). Our results suggest that nuclear accumulation of beta-catenin in CRC is related to CIN and may be of prognostic importance. However, larger studies are needed to verify these findings.

TAP1 down-regulation elicits immune escape and poor prognosis in colorectal cancer.

The anti-tumor immune response has been shown to be of great prognostic importance in colorectal cancer (CRC) and so has the tumors ability for immune evasion. Our aim of this study was to investigate tumor factors that influence immunity. We used a gene expression array to search for potential mechanisms of tumor immune escape. One candidate gene identified was TAP1, involved in antigen presentation by MHC class I. TAP1 protein expression was evaluated by immunohistochemistry in 436 CRC patients of the Colorectal Cancer in Umeå Study cohort. We found a significant association between a downregulated expression of TAP1 and low infiltration of various subtypes of lymphocytes as well as macrophages. A downregulated expression of TAP1 was further found to be independent of molecular characteristics, suggesting TAP1 down-regulation to reach beyond the well described highly immunogenic MSI CRCs. A low expression of TAP1 was also significantly associated with poor prognosis in patients with CRC, a result that stayed significant in tumor front of early stage tumors (stage I-II) through multivariable analyses. Furthermore, we found that TAP1 expression was inversely correlated with methylation at sites in close proximity to the promoter region. In summary, our results show down-regulation of TAP1 to be a general mechanism of tumor immune escape in CRC and a poor prognostic factor in stage I-II CRC patients. We also suggest that methylation of the TAP1 gene may be a putative mechanism for TAP1 downregulation.