Two subtypes of mucinous adenocarcinoma of the colorectum: clinicopathological and genetic features

Noninvasive detection of inflammation-associated colon cancer in a mouse model

Helicobacter bilis-infected Smad3(-/-) mice represent an attractive model of inflammation-associated colon cancer. Most infected mice develop mucinous adenocarcinoma (MUC) by 6 weeks post inoculation (PI); however, approximately one third do not progress to MUC. The ability to predict the development of MUC in mice used in therapeutic studies would confer a considerable saving of time and money. In addition, the inadvertent use of mice without MUC may confound therapeutic studies by making treatments seem falsely efficacious. We assessed both magnetic resonance imaging (MRI) and fecal biomarkers in Helicobacter- and sham-inoculated mice as methods of noninvasively detecting MUC before the predicted onset of disease. Non-contrast-enhanced MRI was able to detect lesions in 58% of mice with histologically confirmed MUC; however, serial imaging sessions produced inconsistent results. MRI was also a labor- and time-intensive technique requiring anesthesia. Alternatively, inflammatory biomarkers isolated from feces at early time points were correlated to later histologic lesions. Fecal expression of interleukin 1β, macrophage inflammatory protein 1α, and regulated on activation, normal T-cell expressed, and secreted at 3 weeks PI correlated significantly with lesion severity at 9 weeks PI. For each biomarker, receiver-operator characteristic curves were also generated, and all three biomarkers performed well at 1 to 3 weeks PI, indicating that the development of MUC can be predicted based on the early expression of certain inflammatory mediators in feces.

Long-term effect of aspirin on colorectal cancer incidence and mortality: 20-year follow-up of five randomised trials

BACKGROUND

High-dose aspirin (≥500 mg daily) reduces long-term incidence of colorectal cancer, but adverse effects might limit its potential for long-term prevention. The long-term effectiveness of lower doses (75-300 mg daily) is unknown. We assessed the effects of aspirin on incidence and mortality due to colorectal cancer in relation to dose, duration of treatment, and site of tumour.

METHODS

We followed up four randomised trials of aspirin versus control in primary (Thrombosis Prevention Trial, British Doctors Aspirin Trial) and secondary (Swedish Aspirin Low Dose Trial, UK-TIA Aspirin Trial) prevention of vascular events and one trial of different doses of aspirin (Dutch TIA Aspirin Trial) and established the effect of aspirin on risk of colorectal cancer over 20 years during and after the trials by analysis of pooled individual patient data.

RESULTS

In the four trials of aspirin versus control (mean duration of scheduled treatment 6·0 years), 391 (2·8%) of 14 033 patients had colorectal cancer during a median follow-up of 18·3 years. Allocation to aspirin reduced the 20-year risk of colon cancer (incidence hazard ratio [HR] 0·76, 0·60-0·96, p=0·02; mortality HR 0·65, 0·48-0·88, p=0·005), but not rectal cancer (0·90, 0·63-1·30, p=0·58; 0·80, 0·50-1·28, p=0·35). Where subsite data were available, aspirin reduced risk of cancer of the proximal colon (0·45, 0·28-0·74, p=0·001; 0·34, 0·18-0·66, p=0·001), but not the distal colon (1·10, 0·73-1·64, p=0·66; 1·21, 0·66-2·24, p=0·54; for incidence difference p=0·04, for mortality difference p=0·01). However, benefit increased with scheduled duration of treatment, such that allocation to aspirin of 5 years or longer reduced risk of proximal colon cancer by about 70% (0·35, 0·20-0·63; 0·24, 0·11-0·52; both p<0·0001) and also reduced risk of rectal cancer (0·58, 0·36-0·92, p=0·02; 0·47, 0·26-0·87, p=0·01). There was no increase in benefit at doses of aspirin greater than 75 mg daily, with an absolute reduction of 1·76% (0·61-2·91; p=0·001) in 20-year risk of any fatal colorectal cancer after 5-years scheduled treatment with 75-300 mg daily. However, risk of fatal colorectal cancer was higher on 30 mg versus 283 mg daily on long-term follow-up of the Dutch TIA trial (odds ratio 2·02, 0·70-6·05, p=0·15).

INTERPRETATION

Aspirin taken for several years at doses of at least 75 mg daily reduced long-term incidence and mortality due to colorectal cancer. Benefit was greatest for cancers of the proximal colon, which are not otherwise prevented effectively by screening with sigmoidoscopy or colonoscopy.

FUNDING

None.

Mucinous adenocarcinoma showing different clinicopathological and molecular characteristics in relation to different colorectal cancer subgroups

BACKGROUND

Mucinous adenocarcinoma (MAC) is frequently reported to be associated with patients of young-age sporadic colorectal cancer (YSCC) and hereditary nonpolyposis colorectal cancer (HNPCC). This study is aimed to investigate whether the clinicopathological characteristics of MAC of HNPCC patients are distinct from those of YSCC patients.

PATIENTS AND METHODS

Eighty-two HNPCC and 68 YSCC patients recorded in the colorectal cancer registry of Chang Gung Memorial Hospital at Linkou, Taiwan, between January 1, 1995 and December 31, 2001 were included in this study. Clinicopathological and molecular variables of MAC and non-MAC of HNPCC and YSCC patients were compared accordingly.

RESULTS

Compared to non-MAC, MAC significantly showed higher frequencies of poor differentiation (32% vs. 8.2%, p = 0.001), advanced tumor stage (76% vs. 47%, p = 0.002), loss of mismatch repair protein (MMR) expression (74% vs. 44%, p = 0.023), and increased MUC2 expression (98% vs. 61%, p < 0.001). MAC of HNPCC patients showed predominant right-sided colon involvement, whereas MAC of YSCC patients displayed predominance in the left colon (79% vs. 22%, p = 0.001). Among the non-MAC counterparts, more differences were detectable including tumor stage, loss of MMR expression, and increased MUC1 expression. Furthermore, both MAC and non-MAC of YSCC patients showed higher frequencies of advanced tumor stage (81% vs. 62%, p = 0.072). In contrast, the incidence of loss of MMR expression in MAC and non-MAC of HNPCC patients is not significantly different (86% vs. 70%, p = 0.323).

CONCLUSIONS

Significantly different tumor localization was observed between mucinous YSCC (left colon predominance) and mucinous HNPCC (right colon predominance).

Mucinous adenocarcinomas with intra-abdominal dissemination: a review of current therapy

Peritoneal carcinomatosis has been considered a terminal disease with a median survival time of 5.2-12.6 months. Systemic chemotherapy and cytoreductive surgery (CRS) have long been used to treat macroscopic disease, with limited success. However, a comprehensive treatment approach involving cytroreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) has evolved into a novel approach for peritoneal carcinomatosis. Surgery removes the primary cancer and any dissemination within the peritoneal cavity and adjuvant HIPEC eradicates macroscopic or microscopic tumor residue, thus reducing the risk for recurrence. This approach offers a new potential treatment option for patients with metastatic disease confined to the peritoneum. The present review provides an update of the most recent data on the current therapy for pseudomyxoma peritonei (PMP) and mucinous colorectal adenocarcinoma (MCA) with metastatic disease confined to the peritoneum.

The prognostic value of p73 overexpression in colorectal carcinoma: a clinicopathologic, immunohistochemical, and statistical study of 204 patients

INTRODUCTION

The protein p73 is the first identified homolog of the tumor suppressor gene p53, but its function in tumor development has not been established. Indeed, the results regarding the p73 implication in colorectal cancers is still controversial.

AIM

We investigated whether the p73 is implicated in colorectal cancer, whether the p73 expression is related to prognosis and whether the p73 expression is correlated with p21-ras or p53.

MATERIALS AND METHODS

We performed a comparative immunohistochemical analysis of p73, p53, and p21ras proteins in primary colorectal tumor with matched normal mucosa and metastasis from 204 patients with colorectal cancer. We correlated these expressions with clinicopathologic variables and we compared the different profiles between nonmucinous carcinoma and mucinous carcinoma.

RESULTS

In this study, we did not find any correlation between p73 expression, sex, age, site, differentiation and stage. Overexpression of p73 was significantly correlated with infiltrating growth pattern (P<0.0001) and nonmucinous carcinoma (P<0.0001). Furthermore, frequency and intensity of p73 expression were marquedly increased from normal mucosa (26%), to primary tumors (75%) and to metastasis (97%). Furthermore, expression of p73 was also correlated with shorter survival period. The prognostic significance of p73 expression remained, even after adjustment for the clinical and pathologic variables. The p73 expression was positively correlated only with p21ras expression (P<0.0001).

CONCLUSIONS

All these findings prove that p73 expression should be considered as a valuable poor prognostic marker. Our data also suggest that TP73 gene may play a role in colorectal carcinoma development.

Gene expression profiling of colorectal mucinous adenocarcinomas

PURPOSE

Although mucinous adenocarcinomas represent 6% to 19% of all colorectal adenocarcinomas, little is known about the genome-wide alterations associated with this malignancy. We have sought to characterize both the gene expression profiles of mucinous adenocarcinomas and their clinicopathologic features.

METHODS

Tumors from 171 patients with primary colorectal cancer were profiled using the Affymetrix HG-U133Plus 2.0 GeneChip with characterization of clinicopathologic data. Gene ontology software was used to identify altered biologic pathways.

RESULTS

Twenty (11.7%) mucinous adenocarcinomas and 151 (89.3%) nonmucinous adenocarcinomas were identified. Mucinous adenocarcinomas were more likely to be diagnosed with lymph node (LN) metastases (75% vs 51%, P = .04) and at a more advanced stage (85% vs 54%, P = .006) but long-term survival (5-y survival 58.9% vs 58.7%, P = NS) was similar. Mucinous adenocarcinomas displayed 182 upregulated and 135 downregulated genes. The most upregulated genes included those involved in cellular differentiation and mucin metabolism (eg, AQP3 + 4.6, MUC5AC +4.2, MUC2 + 2.8). Altered biologic pathways included those associated with mucin substrate metabolism (P = .002 and .02), amino acid metabolism (P = .02), and the mitogen-activated protein kinase cascade (P = .02).

DISCUSSION

Using gene expression profiling of mucinous adenocarcinomas, we have identified the differential upregulation of genes involved in differentiation and mucin metabolism, as well as specific biologic pathways. These findings suggest that mucinous adenocarcinomas represent a genetically distinct variant of colorectal adencarcinoma and have implications for the development of targeted therapies.

Differential colorectal carcinogenesis: Molecular basis and clinical relevance

Colorectal cancer (CCR) is one of the most frequent cancers in developed countries. It poses a major public health problem and there is renewed interest in understanding the basic principles of the molecular biology of colorectal cancer. It has been established that sporadic CCRs can arise from at least two different carcinogenic pathways. The traditional pathway, also called the suppressor or chromosomal instability pathway, follows the Fearon and Vogelstein model and shows mutation in classical oncogenes and tumour suppressor genes, such as K-ras, adenomatous polyposis coli, deleted in colorectal cancer, or p53. Alterations in the Wnt pathway are also very common in this type of tumour. The second main colorectal carcinogenesis pathway is the mutator pathway. This pathway is present in nearly 15% of all cases of sporadic colorectal cancer. It is characterized by the presence of mutations in the microsatellite sequences caused by a defect in the DNA mismatch repair genes, mostly in hMLH1 or hMSH2. These two pathways have clear molecular differences, which will be reviewed in this article, but they also present distinct histopathological features. More strikingly, their clinical behaviours are completely different, having the “mutator” tumours a better outcome than the “suppressor” tumours.

A cohort study of p27 localization in colon cancer, body mass index, and patient survival

Energy balance and the AKT pathway are important in colorectal cancer development and regulate p27 (cyclin-dependent kinase inhibitor-1B/CDKN1B/KIP1), which plays a role in preventing cell cycle progression. However, little is known on the clinical outcome or prognostic significance of p27 alterations in relation to patient body mass index (BMI). Among 630 colon cancers (stage I-IV) in two prospective cohort studies, we detected p27 alterations (cytoplasmic p27 localization or p27 loss) in 500 tumors (79%) by immunohistochemistry. The remaining 130 (21%) tumors were "p27-nuclear+." Cox proportional hazard models computed hazard ratios (HR) of deaths, adjusted for patient and tumoral characteristics, including p53, p21, cyclin D1, KRAS, BRAF, PIK3CA, cyclooxygenase-2, fatty acid synthase (FASN), beta-catenin, microsatellite instability (MSI), CpG island methylator phenotype (CIMP), and long interspersed nucleotide element-1 (LINE-1) hypomethylation. Compared with p27-nuclear+ patients, p27-altered patients experienced low colon cancer-specific [adjusted HR, 0.63; 95% confidence interval (95% CI), 0.42-0.94] and overall mortality (adjusted HR, 0.70; 95% CI, 0.51-0.95), independent of FASN, MSI, CIMP, LINE-1 methylation, and other potential confounders. The effect of p27 alteration on overall mortality significantly differed by BMI (P(interaction) = 0.013); adjusted HR (p27-altered versus p27-nuclear+ tumors) was 0.28 (95% CI, 0.13-0.59) for BMI >or=30 kg/m(2), 0.67 (95% CI, 0.40-1.14) for BMI 25 to 29 kg/m(2), and 0.91 (95% CI, 0.57-1.46) for BMI <25 kg/m(2). Obesity was associated with inferior overall survival among p27-nuclear+ cases (adjusted HR, 3.07; 95% CI, 1.49-6.32; versus nonobese cases), but not among p27-altered cases (adjusted HR, 1.08). In conclusion, p27 alterations in colon cancer are associated with superior prognosis. Adverse prognostic effect of obesity seems limited to patients with nuclear p27 expression, suggesting a host-tumor interaction.

Differential protein immunoexpression profiles in appendiceal mucinous neoplasms: a special reference to classification and predictive factors

Appendiceal mucinous neoplasms have been the focus of considerable debate in recent years. We histologically classified 70 appendiceal mucinous neoplasms into three categories: 32 mucinous adenoma, 23 mucinous neoplasm of uncertain malignant potential, and 15 mucinous adenocarcinomas. Immunohistochemistry was performed for 24 proteins in different functional categories, specifically, oncogenic proteins (bcl-2, beta-catenin, CEA, C-erbB2, c-kit, Cox-2, Cyclin D1, EGFR, Ki-67, NF-kappaB, VEGF), tumor suppressors (E-cadherin, FHIT, hMLH1, p53, p63, smad4), cell-cycle regulators (p21, p27, p16), and mucin proteins (MUC1, MUC2, MUC5AC, MUC6). Our data showed that 9 out of the 24 proteins were more frequently altered in the mucinous adenocarcinoma group than in the mucinous adenoma group (P<0.05), including beta-catenin (13% in mucinous adenoma vs 60% in mucinous adenocarcinoma), CyclinD1 (44 vs 87%), Ki-67 (high labeling index: 31 vs 67%), NF-kappaB (19 vs 60%), VEGF (16 vs 87%), E-cadherin (0 vs 47%), p53 (6 vs 40%), MUC2 (9 vs 67%), and MUC5AC (3 vs 40%). The distinct immunoexpression profile of mucinous neoplasm of uncertain malignant potential was placed between those of mucinous adenoma and mucinous adenocarcinoma (P<0.05). Moreover, the mucinous adenoma, mucinous neoplasm of uncertain malignant potential, and mucinous adenocarcinoma categories displayed differences in terms of the number of altered markers among the nine proteins (P<0.05; mean 1.4 vs 2.6 vs 5.5, respectively). In mucinous adenocarcinoma, the p53 status was related to disease-free survival and overall survival of patients (P<0.05, both). NF-kappaB status and the number of altered protein markers made statistically marginal impacts on disease-free survival; also beta-catenin loss, on overall survival of patients. In conclusion, protein immunoexpression profiles may facilitate the classification of appendiceal mucinous neoplasms. In our study, the three tumor categories of mucinous adenoma, mucinous neoplasm of uncertain malignant potential, and mucinous adenocarcinoma exhibited distinct immunoexpression profiles. Five and more altered protein markers, p53 overexpression, NF-kappaB positivity, and beta-catenin loss were predictive factors of adverse clinical outcomes in appendiceal mucinous adenocarcinomas.

Mucinous histology predicts for poor response rate and overall survival of patients with colorectal cancer and treated with first-line oxaliplatin- and/or irinotecan-based chemotherapy

The objective of this study was to investigate the efficacy of first-line chemotherapy containing irinotecan and/or oxaliplatin in patients with advanced mucinous colorectal cancer. Prognostic factors associated with response rate and survival were identified using univariate and multivariate logistic and/or Cox proportional hazards analyses. The population included 255 patients, of whom 49 (19%) had mucinous and 206 (81%) had non-mucinous colorectal cancer. The overall response rates for mucinous and non-mucinous tumours were 18.4 (95% CI, 7.5–29.2%) and 49% (95% CI, 42.2–55.8%), respectively (P=0.0002). After a median follow-up of 45 months, median overall survival for the mucinous patients was 14.0 months compared with 23.4 months for the non-mucinous group (hazard ratio (HR), 1.74; CI 95%, 1.27–3.31; P=0.0034). After adjustment for significant features by multivariate Cox regression analysis, mucinous histology was associated with poor overall survival (HR, 1.593, 95% CI, 1.05–2.40; P=0.0267), together with performance status ECOG 2, number of metastatic sites ⩾2, and peritoneal metastases. This retrospective analysis shows that patients with mucinous colorectal cancer have poor responsiveness to oxaliplatin/irinotecan-based first-line combination chemotherapy and an unfavourable prognosis compared with non-mucinous colorectal cancer patients.