Unfavourable expression of pharmacologic markers in mucinous colorectal cancer

Unveiling the secrets of gastrointestinal mucous adenocarcinoma survival after surgery with artificial intelligence: A population-based study

BACKGROUND

Research on gastrointestinal mucosal adenocarcinoma (GMA) is limited and controversial, and there is no reference tool for predicting postoperative survival.

AIM

To investigate the prognosis of GMA and develop predictive model.

METHODS

From the Surveillance, Epidemiology, and End Results database, we collected clinical information on patients with GMA. After random sampling, the patients were divided into the discovery (70% of the total, for model training), validation (20%, for model evaluation), and completely blind test cohorts (10%, for further model evaluation). The main assessment metric was the area under the receiver operating characteristic curve (AUC). All collected clinical features were used for Cox proportional hazard regression analysis to determine factors influencing GMA’s prognosis.

RESULTS

This model had an AUC of 0.7433 [95% confidence intervals (95%CI): 0.7424-0.7442] in the discovery cohort, 0.7244 (GMA: 0.7234-0.7254) in the validation cohort, and 0.7388 (95%CI: 0.7378-0.7398) in the test cohort. We packaged it into Windows software for doctors’ use and uploaded it. Mucinous gastric adenocarcinoma had the worst prognosis, and these were protective factors of GMA: Regional nodes examined [hazard ratio (HR): 0.98, 95%CI: 0.97-0.98, P < 0.001)] and chemotherapy (HR: 0.62, 95%CI: 0.58-0.66, P < 0.001).

CONCLUSION

The deep learning-based tool developed can accurately predict the overall survival of patients with GMA postoperatively. Combining surgery, chemotherapy, and adequate lymph node dissection during surgery can improve patient outcomes.

Unveiling the secrets of gastrointestinal mucous adenocarcinoma survival after surgery with artificial intelligence: A population-based study

BACKGROUND

Research on gastrointestinal mucosal adenocarcinoma (GMA) is limited and controversial, and there is no reference tool for predicting postoperative survival.

AIM

To investigate the prognosis of GMA and develop predictive model.

METHODS

From the Surveillance, Epidemiology, and End Results database, we collected clinical information on patients with GMA. After random sampling, the patients were divided into the discovery (70% of the total, for model training), validation (20%, for model evaluation), and completely blind test cohorts (10%, for further model evaluation). The main assessment metric was the area under the receiver operating characteristic curve (AUC). All collected clinical features were used for Cox proportional hazard regression analysis to determine factors influencing GMA’s prognosis.

RESULTS

This model had an AUC of 0.7433 [95% confidence intervals (95%CI): 0.7424-0.7442] in the discovery cohort, 0.7244 (GMA: 0.7234-0.7254) in the validation cohort, and 0.7388 (95%CI: 0.7378-0.7398) in the test cohort. We packaged it into Windows software for doctors’ use and uploaded it. Mucinous gastric adenocarcinoma had the worst prognosis, and these were protective factors of GMA: Regional nodes examined [hazard ratio (HR): 0.98, 95%CI: 0.97-0.98, P < 0.001)] and chemotherapy (HR: 0.62, 95%CI: 0.58-0.66, P < 0.001).

CONCLUSION

The deep learning-based tool developed can accurately predict the overall survival of patients with GMA postoperatively. Combining surgery, chemotherapy, and adequate lymph node dissection during surgery can improve patient outcomes.

Survival Benefits of Postoperative Chemotherapy in Patients With Colorectal Mucinous Adenocarcinoma: An Analysis Utilizing Propensity Score Matching From the Surveillance, Epidemiology, and End Results Database

OBJECTIVE

This study aimed to investigate the characteristics of patients with colorectal mucinous adenocarcinoma (MAC) who benefit from postoperative chemotherapy (POCT) and to develop effective postoperative survival nomograms for predicting overall survival (OS) in colorectal MAC patients.

METHODS

Data of colorectal MAC patients who underwent surgery from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2020 were collected. Patients were grouped based on POCT, and intergroup analysis was performed using 1:1 propensity score matching (PSM). Kaplan-Meier (K-M) curves were used to compare the prognosis between the 2 groups. Cox analysis was employed to identify factors associated with OS in patients with colorectal MAC who underwent POCT. The variance inflation factor (VIF) and bilateral stepwise regression were used to determine factors included in the model. Additionally, a nomogram was constructed to predict postoperative survival outcomes for patients. The discriminative ability of the nomograms was evaluated using the C-index and calibration curve analysis, the decision curve analysis (DCA) assessed the clinical utility of the nomogram, and the receiver operating characteristic (ROC) curve evaluated the nomograms' performance.

RESULTS

This study encompassed 6829 patients with colorectal MAC, among whom 2258 received POCT, and 4571 did not. Whether pre or post PSM, patients in the POCT group consistently exhibited a superior median OS compared to those in the postoperative non-chemotherapy group (P < .0001). For colorectal MAC patients undergoing POCT, OS was correlated with factors such as patient age, carcinoembryonic antigen levels, tumor deposits, perineural invasion (PNI), lymph node examination count, T staging, and Grade staging. Notably, a significant chemotherapy advantage was observed in patients without perineural invasion, those with lymph node examination counts exceeding 12, and patients with moderately differentiated tumors. The overall colorectal MAC patient postoperative OS predictive nomogram demonstrated a C-index of .74, with a calibration curve near the diagonal and a DCA curve indicating positive net benefits. In comparison to TNM staging, the ROC curves of the nomogram at 1 year, 3 years, and 5 years demonstrated superior predictive capabilities (AUC: .80 vs .71, .78 vs .71, .77 vs .70).

CONCLUSION

This study revealed the characteristics of colorectal MAC patients who benefit from POCT and established effective prognostic nomograms, which can aid clinicians in designing personalized treatment plans for individual patients and promote precision medicine.

Adjuvant Radiotherapy Is Not Necessary for Stage III Mucinous Rectal Cancer: Evidence Based on Long Survival Analysis from SEER Data

BACKGROUND

Although rectal mucinous adenocarcinoma (RMC) is less sensitive to radiotherapy, adjuvant radiotherapy is still recommended for RMC patients. This study aimed to explore whether adjuvant radiotherapy is necessary for stage III RMC.

METHODS

Data of patients with stage III RMC were obtained from the National Cancer Institute's SEER database (2004-2015). The survival rates were calculated by Kaplan-Meier method and compared by log-rank test. Univariate and multivariate Cox regression analyses were used to assess the impact of clinicopathological parameters on overall survival (OS) and cancer-specific survival (CSS).

RESULTS

RMC has a worse T and N stage at diagnosis than rectal adenomatous carcinoma (RAC) (all p < 0.001). Multivariate Cox regression analyses revealed that histopathological type MC was an independent poor prognostic factor for OS (HR 1.27; 95%CI 1.14-1.41; p < 0.001) and CSS (HR 1.34; 95%CI 1.18-1.51; p < 0.001). Subgroup analysis based on different treatment regimens showed no significant difference between chemotherapy group and chemotherapy plus radiotherapy group. After the propensity score matching, no significant difference was also found in OS and CSS between chemotherapy group and chemotherapy plus radiotherapy group.

CONCLUSIONS

RMC is an independent poor prognostic factor for OS and CSS. Adjuvant radiotherapy for RMC was not beneficial in improving survival outcomes.

Adjuvant chemotherapy improves long-term survival in pathologic stage III rectal mucinous adenocarcinoma after pre-operative chemoradiotherapy

PURPOSE

The benefits of adjuvant chemotherapy remain debated rectal mucinous adenocarcinoma (MC). Our study aims to delve into the efficacy of adjuvant chemotherapy in pathologic stage III rectal MC by a large population-based database.

METHODS

The Chi-square test was performed to examine the parameters between treatment groups. The overall survival (OS) and cancer-specific survival (CSS) of treatment groups were conducted by using the Kaplan-Meier method. The impact of factors on survival was assessed using Cox regression analyses. To balance the covariates and reduce the selection bias, we employed propensity score matching (PSM) to narrow the differences between treatment groups.

RESULTS

The median follow-up time for overall patients was 80 months. In the pre-operative chemoradiotherapy (pre-CRT) group, patients who received adjuvant chemotherapy had significantly better 5-year OS and CSS. Multivariate analyses found that adjuvant chemotherapy was associated with better OS (p < 0.001, HR (95% CI): 0.66 (0.51-0.86)) and CSS (p = 0.012, HR (95% CI): 0.71 (0.54-0.93)). However, adjuvant chemotherapy was not an independent prognosis factor in both OS (p = 0.149, HR (95% CI): 0.76 (0.53-1.1); Supplement Table 1) and CSS (p = 0.183, HR (95% CI): 0.74 (0.48-1.15)) in patients who did not receive pre-CRT. After PSM, similar results were found in the pre-CRT and the no pre-CRT groups.

CONCLUSION

In conclusion, our population-based retrospective cohort study indicates that the effects of adjuvant chemotherapy were associated with the pre-CRT status in patients with stage III rectal MC. In patients who underwent pre-CRT, the receipt of adjuvant chemotherapy was associated with better survival outcomes. Conversely, adjuvant chemotherapy does not seem to confer significant survival benefits to patients without pre-CRT.

ABCG2 Gene and ABCG2 Protein Expression in Colorectal Cancer-In Silico and Wet Analysis

ABCG2 (ATP-binding cassette superfamily G member 2) is a cell membrane pump encoded by the ABCG2 gene. ABCG2 can protect cells against compounds initiating and/or intensifying neoplasia and is considered a marker of stem cells responsible for cancer growth, drug resistance and recurrence. Expression of the ABCG2 gene or its protein has been shown to be a negative prognostic factor in various malignancies. However, its prognostic significance in colorectal cancer remains unclear. Using publicly available data, ABCG2 was shown to be underexpressed in colon and rectum adenocarcinomas, with lower expression compared to both the adjacent nonmalignant lung tissues and non-tumour lung tissues of healthy individuals. This downregulation could result from the methylation level of some sites of the ABCG2 gene. This was connected with microsatellite instability, weight and age among patients with colon adenocarcinoma, and with tumour localization, population type and age of patients for rectum adenocarcinoma. No association was found between ABCG2 expression level and survival of colorectal cancer patients. In wet analysis of colorectal cancer samples, neither ABCG2 gene expression, analysed by RT-PCR, nor ABCG2 protein level, assessed by immunohistochemistry, was associated with any clinicopathological factors or overall survival. An ABCG2-centered protein-protein interaction network build by STRING showed proteins were found to be involved in leukotriene, organic anion and xenobiotic transport, endodermal cell fate specification, and histone methylation and ubiquitination. Hence, ABCG2 underexpression could be an indicator of the activity of certain signalling pathways or protein interactors essential for colorectal carcinogenesis.

Single-cell profiling reveals differences between human classical adenocarcinoma and mucinous adenocarcinoma

Colorectal cancer is a highly heterogeneous disease. Most colorectal cancers are classical adenocarcinoma, and mucinous adenocarcinoma is a unique histological subtype that is known to respond poorly to chemoradiotherapy. The difference in prognosis between mucinous adenocarcinoma and classical adenocarcinoma is controversial. Here, to gain insight into the differences between classical adenocarcinoma and mucinous adenocarcinoma, we analyse 7 surgical tumour samples from 4 classical adenocarcinoma and 3 mucinous adenocarcinoma patients by single-cell RNA sequencing. Our results indicate that mucinous adenocarcinoma cancer cells have goblet cell-like properties, and express high levels of goblet cell markers (REG4, SPINK4, FCGBP and MUC2) compared to classical adenocarcinoma cancer cells. TFF3 is essential for the transcriptional regulation of these molecules, and may cooperate with RPS4X to eventually lead to the mucinous adenocarcinoma mucus phenotype. The observed molecular characteristics may be critical in the specific biological behavior of mucinous adenocarcinoma.

Comparison of clinicopathological characteristics of mucinous adenocarcinoma and conventional adenocarcinoma of gallbladder

BACKGROUND

Gallbladder mucinous adenocarcinoma (GBMAC) is a rare type of gallbladder malignant tumor, whereas little is known regarding the clinicopathological features and surgical outcomes of GBMAC.

METHODS

From January 2000 till December 2015, 54 GBMAC patients who underwent curative-intent surgical resection at our institution were retrospectively reviewed. We compared the clinicopathological features and surgical outcomes of these GBMAC patients with a relatively large cohort of surgically resected conventional gallbladder adenocarcinoma (GBAC) patients without existence of mucinous components.

RESULTS

The clinicopathological features of GBMAC were significantly different from conventional GBAC, including poorer tumor differentiation (P < 0.001), higher CA19-9 levels (P < 0.001), larger tumor sizes (P = 0.020), advanced AJCC tumor stage (P = 0.002), higher frequency of liver parenchyma invasion (P = 0.020), portal vein invasion (P = 0.003), lymph node metastasis (P = 0.016), lympho-vascular invasion (P < 0.001) and perineural invasion (P = 0.025). Relative to conventional GBAC patients, GBMAC patients showed significantly worse overall survival (OS) (29.0 vs 15.0 months; P < 0.001). Multivariate analysis confirmed the surgical margin (P = 0.046), tumor differentiation grade (P = 0.018), lymph node metastasis (P = 0.024), and presence of signet-ring cell component (P = 0.005) as independent prognostic factors influencing OS of patients with GBMAC.

CONCLUSION

GBMAC always had more aggressive biological behaviors and poor survival outcomes even after curative surgery. GBMAC patients with the presence of signet-ring cell component showed even worse survival outcome.

Correlation of Immunological and Histopathological Features with Gene Expression-Based Classifiers in Colon Cancer Patients

The purpose of this study was to evaluate the association between four distinct histopathological features: (1) tumor infiltrating lymphocytes, (2) mucinous differentiation, (3) tumor-stroma ratio, plus (4) tumor budding and two gene expression-based classifiers—(1) consensus molecular subtypes (CMS) plus (2) colorectal cancer intrinsic subtypes (CRIS). All four histopathological features were retrospectively scored on hematoxylin and eosin sections of the most invasive part of the primary tumor in 218 stage II and III colon cancer patients from two independent cohorts (AMC-AJCC-90 and AC-ICAM). RNA-based CMS and CRIS assignments were independently obtained for all patients. Contingency tables were constructed and a χ2 test was used to test for statistical significance. Odds ratios with 95% confidence intervals were calculated. The presence of tumor infiltrating lymphocytes and a mucinous phenotype (>50% mucinous surface area) were strongly correlated with CMS1 (p < 0.001 and p = 0.008) and CRIS-A (p = 0.006 and p < 0.001). The presence of mucus (≥ 10%) was associated with CMS3: mucus was present in 64.1% of all CMS3 tumors (p < 0.001). Although a clear association between tumor-stroma ratio and CMS4 was established in this study (p = 0.006), still 32 out of 61 (52.5%) CMS4 tumors were scored as stroma-low, indicating that CMS4 tumors cannot be identified solely based on stromal content. Higher budding counts were seen in CMS4 and CRIS-B tumors (p = 0.045 and p = 0.046). No other associations of the measured parameters were seen for any of the other CRIS subtypes. Our analysis revealed clear associations between histopathologic features and CMS or CRIS subtypes. However, identification of distinct molecular subtypes solely based on histopathology proved to be infeasible. Combining both molecular and morphologic features could potentially improve patient stratification.

Mucinous histology is associated with poor prognosis in locally advanced colorectal adenocarcinoma treated with postoperative first-line adjuvant chemotherapy: A systematic review and meta-analysis

PURPOSE

Postoperative adjuvant chemotherapy followed surgery is the standard management for localized advanced colorectal carcinoma (CRC). Mucinous adenocarcinoma (MAC) is a peculiar histological subtype of CRC, but the prognosis of MAC patients is controversial. The objective of this study is to assess the implication of MAC in survival of patients treated with surgery and firs-line adjuvant chemotherapy.

METHODS

Studies describing outcomes for advanced MAC and non-specific adenocarcinoma (AC) of CRC patients treated with first-line postoperative adjuvant chemotherapy followed surgery were searched in PubMed, Embase, Medline, EBSCO, Wiley, and Cochrane Library (January 1963-August 2021). Hazard ratios (HRs) of overall survival (OS), disease-free survival (DFS) and cancer-specific survival (CSS) for MAC to AC were extracted. Random-effects model was used for calculating the pooled HRs and 95% confidence interval (CI).

RESULTS

This meta-analysis is comprised of 8 studies involving a total of 124,303 CRC patients treated with first-line adjuvant chemotherapy followed surgery. The pooled HR for MAC was 1.23 (95% CI, 1.07-1.41, p < 0.01, I² = 80%), and the DFS (HR, 2.95, 95% CI, 1.22-7.14) of MAC patients were significantly poorer than AC patients. Similar results were also observed in stage III and FOLFOX regimen subgroups.

CONCLUSION

MAC was a risk factor for prognosis of localized advanced CRC patients treated with postoperative first-line adjuvant chemotherapy. Thus, the role of first-line adjuvant chemotherapy regimens should be further studied in these MAC patients.

OUP accepted manuscript

Background

Limited studies have suggested that mucinous histology is associated an attenuated response to anti-epidermal growth factor receptor (EGFR) therapy.

Methods

We conducted a single-institution, retrospective study to review the anti-EGFR response and the molecular profile of patients with left-sided microsatellite stable RAS/BRAF wild-type mucinous metastatic colorectal cancer.

Results

In comparison to nonmucinous population (n = 98), mucinous histology (n = 20) was associated with a younger age (48 vs 54, P = .02), wild-type APC (80% vs 15.3%, P < .0001), and wild-type TP53 (40% vs 8.2%, P = .001). Guanine nucleotide binding protein, alpha stimulating (GNAS) mutations were exclusively found in mucinous tumors (20% vs 0, P < .0001). Genomic alterations associated with resistance to anti-EGFR therapy, such as ERBB2 amplification, PIK3CA mutation, MAP2K1 mutation, and KRAS amplification, were identified in patients with left-sided RAS/BRAF wild-type mucinous metastatic colorectal cancer. Mucinous histology was not associated with a worse outcome than non-mucinous histology (34.3 vs 42.2 months, P = .85). However, patients with left-sided RAS/BARF wild-type mucinous colorectal cancer treated with first-line anti-EGFR therapy had significantly worse progression-free survival (4 vs 6.5 months, hazard ratio [HR] = 5.3, 95% confidence interval [CI] 1.3-21.7, P = .01) than patients treated with the first-line vascular endothelial growth factor A antibody, bevacizumab. Anti-EGFR therapy was associated with limited responses and a short PFS across all lines of therapy in 12 patients with left-sided RAS/BRAF wild-type mucinous colorectal cancer.

Conclusions

Mucinous histology is associated with diminished benefits from anti-EGFR therapy in patients with left-sided RAS/BRAF wild-type colorectal cancer. These patients should be considered for bevacizumab-based therapy in the first- and second-line settings.

Clinical significance of mucinous component in colorectal adenocarcinoma: a propensity score-matched study

Background

This study aims to investigate the clinical significance and prognostic value of mucinous component (MC) in colorectal adenocarcinoma (AC).

Methods

Patients with colorectal AC and AC with MC (ACMC) (1–100%) underwent surgical resection between January 2007 and February 2018 were retrospectively reviewed. Propensity score matching (PSM) was performed according to a 1:1 ratio. Receiver-operating characteristic (ROC) curve was used to identify the optimal cut-off value of MC ratio for prognostic prediction. The clinicopathological features and 3-year overall survival (OS) of AC patients, mucinous adenocarcinoma (MAC) (MC > 50%) patients, and ACMC (1–50%) patients were compared before and after matching. Multivariable analysis was used for analyzing independent risk factors related to prognosis.

Results

A total of 532 patients were enrolled in this study. Patients with AC, MAC, and ACMC (1–50%) exhibited different clinicopathological features. However, their 3-year OS rates were similar (82.00% vs. 74.11% vs. 81.48%, P = 0.38). After matching, ROC curve determined 70% as the optimal cut-off value. And patients with ACMC > 70% had a much poorer 3-year OS compared with ACMC (1–70%) patients and AC patients (47.37% vs. 86.15% vs. 79.76%, P < 0.001). In addition, ACMC > 70% was revealed as a risk factor for poor survival in univariate analysis (HR = 1.643, 95%CI = 1.025–2.635, P = 0.039), though not an independent risk factor in multivariable analysis (HR = 1.550, 95%CI = 0.958–2.507, P = 0.074).

Conclusions

MAC is usually diagnosed at an advanced stage. MAC has a similar survival with AC and ACMC (1–50%) patients before and after matching. Patients with ACMC > 70% exhibited a much poorer OS, and should be given more clinical attention.

Rapid progression of colonic mucinous adenocarcinoma with immunosuppressive condition: A case report and review of literature

BACKGROUND

Colorectal mucinous adenocarcinoma is a rare subtype of colorectal cancer and is characterized by an abundance of mucin in the tumor. In addition, the colorectal mucinous adenocarcinoma often demonstrates poor differentiation in the histology of tumor cells and poor prognosis compared with those with adenocarcinoma. Here, we present the case of a young woman with colonic mucinous adenocarcinoma showing significantly rapid progression within four months of immunosuppressant therapy for Henoch–Schönlein purpura.

CASE SUMMARY

Here we report a rare case of ascending colon mucinous adenocarcinoma with lymph node and liver metastases which developed and progressed rapidly within four months during the treatment of Henoch–Schönlein purpura using corticosteroids. The systemic screening examinations showed no tumors before the immunosuppressant therapy. Fortunately, the patient was successfully treated with chemotherapy.

CONCLUSION

While no direct evidence that the immunosuppressants accelerated the tumor development, the case presenta tion and review of the literature demonstrated that surveillance for malignancies before and during treatment with immunosuppressive agents is essential.

First-line therapy of bevacizumab plus chemotherapy versus cetuximab plus chemotherapy for metastatic colorectal cancer patients with mucinous adenocarcinoma or mucinous component

Background

To compare the efficacy of first‐line bevacizumab plus chemotherapy with cetuximab plus chemotherapy based on the stratification of metastatic colorectal cancer (mCRC) patients with mucinous adenocarcinoma (MA) or mucinous component (MC).

Methods

A retrospective study involving all mCRC patients receiving first‐line bevacizumab‐based or cetuximab‐based chemotherapy at our hospital from September 2013 to January 2020 was conducted. Overall survival (OS), progression‐free survival (PFS), and objective response rate (ORR) were compared between the cetuximab‐chemotherapy group and the bevacizumab‐chemotherapy group on the basis of the conventional pathological classification of MA or MC.

Results

A total of 620 patients with mCRC were included in our study, consisting of 141 (22.7%) patients with MA/MC and 479 (77.3%) patients with non‐mucinous adenocarcinoma (NMA). In the MA/MC cohort, patients who were treated with bevacizumab‐based chemotherapy were associated with significantly better OS than those treated with cetuximab‐base chemotherapy (30.0 vs. 26.3 months, p = 0.002), irrespective of tumor sites. The efficacy of bevacizumab‐based chemotherapy was higher in nearly all subgroups as shown in the subgroup analysis. In the NMA cohort, median OS was better in the cetuximab plus chemotherapy group than that in the bevacizumab plus chemotherapy group (32.2 vs. 27.0 months, p = 0.005) for left‐side mCRC patients, whereas OS was significantly longer in the bevacizumab plus chemotherapy group for right‐side mCRC patients (26.0 vs. 20.9 months, p = 0.013).

Conclusion

Conventional pathological classification (e.g. MA/MC) should be considered when tailoring the individualized optimal treatment for mCRC. Bevacizumab plus chemotherapy as first‐line therapy may be the optimal option for patients with MA/MC.

Resistance to Cell Death in Mucinous Colorectal Cancer-A Review

Mucinous colorectal cancer (CRC) is estimated to occur in approximately 10-15% of CRC cases and is characterized by abundant extracellular mucin. Mucinous CRC is frequently associated with resistance to apoptosis. Inferior prognosis is observed in mucinous CRC, particularly in rectal cancer and metastatic cases. Mucins are heavily glycosylated secretory or transmembrane proteins that participate in protection of the colonic epithelium. MUC2 overexpression is a hallmark of mucinous CRCs. Mucinous CRC is associated with KRAS and BRAF mutation, microsatellite instability and the CpG island methylator phenotype. Mutations of the APC gene and p53 mutations which are characteristic non-mucinous colorectal adenocarcinoma are less common in mucinous CRC. Both physical and anti-apoptotic properties of mucin provide mechanisms for resistance to cell death. Mucin glycoproteins are associated with decreased expression of pro-apoptotic proteins, increased expression of anti-apoptotic proteins and increased cell survival signaling. The role for BCL-2 proteins, including BCL-X_L, in preventing apoptosis in mucinous CRC has been explored to a limited extent. Additional mechanisms opposing cell death include altered death receptor expression and altered mutation rates in genes responsible for chemotherapy resistance. The roles of alternate cell death programs including necroptosis and pyroptosis are not well understood in mucinous CRC. While the presence of MUC2 is associated with an immunosuppressive environment, the tumor immune environment of mucinous CRC and the role of immune-mediated tumor cell death likewise require further investigation. Improved understanding of cell death mechanisms in mucinous CRC may allow modification of currently used regimens and facilitate targeted treatment.

The Clinical Significance of Promoter Methylation of Fluoropyrimidine Metabolizing and Cyclooxygenase Genes in Colorectal Cancer

AIMS

This study investigated the impact of promoter methylation of flouropyrimidine (FP) metabolizing and cyclooxygenase 2 (COX2) genes on their mRNA expression and on the clinical outcome of colorectal cancer (CRC) patients.

METHODS

Methylation specific-PCR and real time-PCR of thymidylate synthase (TS), thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD) and COX2 were performed at baseline and after 3 and 6 months of FP therapy. Pairwise comparisons were conducted between the subgroups of CRC patients. The event free survival (EFS) and the hazard of progression were estimated by univariate and multivariate analyses.

RESULTS

At baseline CRC patients, both TS and TP were overexpressed, in spite of the unmethylation of TS and the full methylation of TP genes. Significant downexpression of DPD and COX2 were associated their promoter's methylation. At the end of FP therapy, TS, DPD and COX2 were overexpressed by 7.52, 2.88 and 3.45 folds, respectively, while TP was downexpressed by 0.54 fold. However, no change was observed in the methylation status of genes with FP therapy. Pairwise comparisons revealed significant difference in the expression and the methylation status of genes according to the clinicopathological characters of CRC patients either at baseline or after FP therapy. The overexpression of DPD and COX2 genes were indicators for a poor EFS of CRC patients. Also, the high level of COX2 expression was found to be significantly correlated with the hazard of progression (HR = 1.73, 95% CI = 1.02-3.03).

CONCLUSION

The promoter methylation of FP metabolizing and COX2 genes has significant impact on the expression and the treatment outcome of CRC patients.

Prognostic implications of mucinous histology in stage III colon cancer with the receipt of adjuvant chemotherapy

Background

There is still a debate about the survival benefit of chemotherapy in stage III mucinous colon cancer, we then conduct a comprehensive assessment of the efficacy of adjuvant chemotherapy in this population.

Methods

The data used in the current study were extracted from the Surveillance, Epidemiology and End Results (SEER) database. Chi-squared (χ²) test was used to compared patient characteristics according to the histology. The outcome of the survival analysis used in the current study was cancer-specific survival (CSS). Univariable and multivariable analyses were carried out using the Cox proportional hazards regression models to evaluate the prognostic characteristics associated with CSS of colon cancer. And the risks of mortality were presented as hazard ratios (HRs) with 95% confidence intervals (CIs).

Results

A total of 68,976 patients diagnosed with stage III colon cancer were included in our analyses, including mucinous adenocarcinoma (MAC, N=6,592) and non-mucinous adenocarcinoma (NMA, N=62,384). In NMA, the receipt of chemotherapy had 46.0% independently decreased risk of colon cancer-specific mortality compared to non-chemotherapy group (HR =0.540, 95% CI: 0.523-0.558, P<0.001). In MAC, the receipt of chemotherapy had 37.7% independently decreased risk of colon cancer-specific mortality compared to non-chemotherapy group (HR =0.623, 95% CI: 0.566-0.685, P<0.001).

Conclusions

MAC was associated with worse prognosis and was less responsive to chemotherapy compared with NMA in stage III colon cancer. However, stage III mucinous colon cancer still need to be treated with chemotherapy because of the significant survival benefit and specialized treatment plans for MAC were quite necessary in the future.

Identification of differentially expressed genes between mucinous adenocarcinoma and other adenocarcinoma of colorectal cancer using bioinformatics analysis

Objective

As a unique histological subtype of colorectal cancer (CRC), mucinous adenocarcinoma (MC) has a poor prognosis and responds poorly to treatment. Genes and markers related to MC have not been reported.

Methods

To identify biomarkers involved in development of MC compared with other common adenocarcinoma (AC) subtypes, four datasets were obtained from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were identified using GEO2R. A protein–protein interaction network was constructed. Functional annotation for DEGs was performed via DAVID, Metascape, and BiNGO. Significant modules and hub genes were identified using Cytoscape, and expression of hub genes and relationships between hub genes and MC were analyzed.

Results

The DEGs were mainly enriched in negative regulation of cell proliferation, bicarbonate transport, response to peptide hormone, cell–cell signaling, cell proliferation, and positive regulation of the canonical Wnt signaling pathway. The Venn diagram revealed eight significant hub genes: CXCL9, IDO1, MET, SNAI2, and ZEB2 were highly expressed in MC compared with AC, whereas AREG, TWIST1, and ZEB1 were expressed at a low level. AREG and MET might be significant biomarkers for MC.

Conclusion

The identified DEGs might help elucidate the pathogenesis of MC, identify potential targets, and improve treatment for CRC.

Mucinous Adenocarcinoma of the Rectum: A Whole Genome Sequencing Study

Introduction

Mucinous adenocarcinoma of the rectum is an infrequently encountered histological subtype that is associated with an impaired response to chemoradiotherapy and a worse overall prognosis. A genomic profile analysis of mucinous rectal tumors has not yet been performed. The aim of this study was to comprehensively describe the burden of somatic mutations and copy number variation as well as perform mutational signature and microbial analysis of an in-house collected cohort of mucinous adenocarcinoma of the rectum.

Methods

Genomic DNA was extracted from 10 cases of mucinous rectal cancer and matched normal tissue. Whole genome sequencing (WGS) was carried out on these 10 cases and a comprehensive bioinformatic analysis was undertaken.

Results

The average number of SNVs, InDels and SVs in the cohort was 16,600, 1,855, and 120, respectively. A single case was MSI-H. KRAS mutations were found in 70% of cases while TP53 was mutated in only 40% of cases. CNA gain was identified on chromosomes 7, 8, 12, 13, and 20 while CNA loss was found on chromosomes 4, 8, 17, and 18 corresponding to oncogenes and tumor suppressor genes, respectively. Overall mucinous rectal cancers are more likely to be MSI-H and to have KRAS, BRAF, and PIK3CA mutations when compared to rectal adenocarcinoma NOS. Microbial analysis demonstrated an abundance of Fusobacterium nucleatum in tumor samples compared to normal tissue.

Conclusion

This study provides a detailed WGS analysis of 10 cases of mucinous rectal cancer. It demonstrates an important lesson in tumor biology in that histologically similar tumors can have extensive differences at the genomic level. This study is relevant as it raises important questions about the relationship between bacteria and malignancy.

Tumor clinicopathological characteristics and their prognostic value in mucinous colorectal carcinoma

Aim: This study analyzed clinicopathological features of colorectal mucinous carcinoma and their prognostic values. Patients & method: This study enrolled 265 patients with mucinous colorectal cancer. Clinicopathological information and prognosis were reviewed retrospectively. Kaplan-Meier method, log- rank test and COX proportional hazard regression models were used. Results: In postoperative mucinous carcinoma patients (median age 56, 119 [44.9%] female), advanced tumor stage (odds ratio [OR]: 2.378; 95% CI: 1.512-3.741; p = 0.0002), poor differentiation (OR: 1.896; CI: 1.217-2.955; p = 0.0047) and right-sided tumors (OR: 2.421; CI: 1.145-5.102; p = 0.0206) were associated with shorter overall survival. Appendiceal/ileocecal cecal tumors were not different for prognosis. Conclusion: Mucinous colorectal carcinoma exhibits distinct tumor characteristics. Poor differentiation, advanced stage at presentation and the right side serve as negative prognostic factors.

Mucinous colorectal adenocarcinoma: clinical pathology and treatment options

Mucinous colorectal adenocarcinoma is a distinct subtype of colorectal cancer (CRC) characterized by the presence of abundant extracellular mucin which accounts for at least 50% of the tumor volume. Mucinous colorectal adenocarcinoma is found in 10%–20% of CRC patients and occurs more commonly in female and younger patients. Moreover, mucinous colorectal adenocarcinoma is more frequently located in the proximal colon and diagnosed at an advanced stage. Based on its molecular context, mucinous colorectal adenocarcinoma is associated with the overexpression of mucin 2 (MUC2) and mucin 5AC (MUC5AC) proteins. At the same time, it shows higher mutation rates in the fundamental genes of the RAS/MAPK and PI3K/Akt/mTOR pathways. Mucinous colorectal adenocarcinoma also shows higher rates of microsatellite instability (MSI) than non-mucinous colorectal adenocarcinoma which might correlate it with Lynch syndrome and the CpG island methylator phenotype. The prognosis of mucinous colorectal adenocarcinoma as to non-mucinous colorectal adenocarcinoma is debatable. Further, the impaired responses of mucinous colorectal adenocarcinoma to palliative or adjuvant chemotherapy warrant more studies to be performed for a specialized treatment for these patients. In this review, we discuss the molecular background and histopathology of mucinous colorectal adenocarcinoma, and provide an update on its prognosis and therapeutics from recent literatures.

Amide proton transfer imaging to predict tumor response to neoadjuvant chemotherapy in locally advanced rectal cancer

BACKGROUND AND AIM

The amount of proteins and peptides can be estimated with amide proton transfer (APT) imaging. Previous studies demonstrated the usefulness of APT imaging to predict tumor malignancy. We determined whether APT imaging can predict the tumor response to neoadjuvant chemotherapy (NAC) in patients with locally advanced rectal cancer (LARC).

METHODS

Seventeen patients with LARC who underwent a pretherapeutic magnetic resonance examination including APT imaging and NAC (at least two courses) were enrolled. The APT-weighted imaging (WI) signal intensity (SI) (%) was defined as magnetization transfer ratio asymmetry (MTR_asym ) at the offset of 3.5 ppm. Each tumor was histologically evaluated for the degree of degeneration and necrosis and then classified as one of five histological Grades (0, none; 1a, less than 1/3; 1b, 1/3 to 2/3; 2, more than 2/3; 3, all). We compared the mean APTWI SIs of the tumors between the Grade 0/1a/1b (low-response group) and Grade 2/3 (high-response group) by Student's t-test. We used receiver operating characteristics curves to determine the diagnostic performance of the APTWI SI for predicting the tumor response.

RESULTS

The mean APTWI SI of the low-response group (n = 12; 3.05 ± 1.61%) was significantly higher than that of the high-response group (n = 5; 1.14 ± 1.13%) (P = 0.029). The area under the curve for predicting the tumor response using the APTWI SI was 0.87. When ≥2.75% was used as an indicator of low-response status, 75% sensitivity and 100% specificity of the APTWI SI were obtained.

CONCLUSION

Pretherapeutic APT imaging can predict the tumor response to NAC in patients with LARC.

Survival difference between mucinous vs. non-mucinous colorectal cancer following cytoreductive surgery and intraperitoneal chemotherapy

BACKGROUND

It is believed that the oncologic behavior of mucinous colorectal adenocarcinoma (MC) is different from non-mucinous adenocarcinoma (NMC). The aim of the study is to compare long-term survivals between patients with MC and those with NMC following cytoreductive surgery (CRS) and intraperitoneal chemotherapy (IPC).

METHODS

This was a retrospective study of prospectively collected data of patients with peritoneal metastases of colorectal origin following CRS and IPC. Group I included patients with MC which was defined as being composed of >50% extracellular mucin. Group II included those with NMC. Subgroup analysis was performed according to the location of primary tumor.

RESULTS

A total of 213 patients were included in this study. The two groups had similar hospital mortality, high dependency unit stay. MC group had a significantly longer mean intensive care unit (ICU) stay (p = .037) and total hospital stay (p = .037). There was no significant difference in overall survival (OS) and disease-free survival (DFS) between two groups (p = .657 and p = .938, respectively). Multivariate analysis showed that the presence of mucin was not an independent negative prognostic factor for OS (p = .190).

CONCLUSION

In summary, patients with MC had a similar long-term survival outcome with those with NMC following CRS and IPC.

Epidermal growth factor receptor (EGFR) inhibitor PD153035 reverses ABCG2-mediated multidrug resistance in non-small cell lung cancer: In vitro and in vivo

One of the major mediators of multidrug resistance (MDR) in non-small cell lung cancer (NSCLC) is the overexpression of ATP-binding cassette subfamily G member 2 (ABCG2). In this study, we conducted in vitro and in vivo experiments to determine whether PD153035, an inhibitor of EGFR, could reverse ABCG2-mediated MDR in human NSCLC and transfected cells overexpressing ABCG2. The efficacy of SN-38, topotecan, and mitoxantrone (MX) were significantly increased by PD153035, PD153035 significantly reversed ABCG2-mediated MDR by attenuating the efflux activity of this transporter. In addition, PD153035 significantly down-regulated the expression of the ABCG2 transporter protein. Furthermore, a combination of PD153035 and topotecan, exhibited significant synergistic anticancer activity against mice xenografted with human H460/MX20 cells. These results, provided that they can be extrapolated to humans, suggest that the combination of topotecan and PD153035 could be a promising therapeutic strategy to attenuate the resistance to topotecan, as well as other anticancer drugs, mediated by the overexpression of ABCG2.

Drug resistance related to aberrant glycosylation in colorectal cancer

Colorectal cancer (CRC) is the fourth leading cause of cancer-related deaths in the world. Drug resistance of tumour cells remains the main challenge toward curative treatments efficiency. Several epidemiologic studies link emergence and recurrence of this cancer to metabolic disorders. Glycosylation that modifies more than 80% of human proteins is one of the most widepread nutrient-sensitive post-translational modifications. Aberrant glycosylation participates in the development and progression of cancer. Thus, some of these glycan changes like carbohydrate antigen CA 19-9 (sialyl Lewis a, sLea) or those found on carcinoembryonic antigen (CEA) are already used as clinical biomarkers to detect and monitor CRC. The current review highlights emerging evidences accumulated mainly during the last decade that establish the role played by altered glycosylations in CRC drug resistance mechanisms that induce resistance to apoptosis and activation of signaling pathways, alter drug absorption and metabolism, and led to stemness acquisition. Knowledge in this field of investigation could aid to the development of better therapeutic approaches with new predictive biomarkers and targets tied in with adapted diet.

Implications of ABCG2 Expression on Irinotecan Treatment of Colorectal Cancer Patients: A Review

BACKGROUND

One of the main chemotherapeutic drugs used on a routine basis in patients with metastatic colorectal cancer ((m)CRC) is the topoisomerase-1 inhibitor, irinotecan. However, its usefulness is limited by the pre-existing or inevitable development of resistance. The ATP-binding cassette (ABC) transporter ABCG2/breast cancer resistance protein (BRCP) through its function in xenobiotic clearance might play an important role in irinotecan resistance. With a goal to evaluate the clinical significance of ABCG2 measurements, we here review the current literature on ABCG2 in relation to irinotecan treatment in CRC patients.

RESULTS

Few studies have evaluated the association between ABCG2 gene or protein expression and prognosis in CRC patients. Discordant results were reported. The discrepancies might be explained by the use of different criteria for interpretation of results in the immunohistochemistry studies. Only one large study evaluated the ABCG2 protein expression and efficacy of irinotecan in mCRC (CAIRO study, n = 566). This study failed to demonstrate any correlation between ABCG2 protein expression in the primary tumor and response to irinotecan-based treatment. We recently raised questions on how to evaluate ABCG2 immunoreactivity patterns, and the results in the CAIRO study might be influenced by using a different scoring protocol than the one proposed by us. In contrast, our recent exploratory study of ABCG2 mRNA expression in 580 patients with stage III primary CRC (subgroup from the randomized PETACC-3 study) indicated that high ABCG2 tumor tissue mRNA expression might be predictive for lack of efficacy of irinotecan.

CONCLUSION

The biological role of ABCG2 in predicting clinical irinotecan sensitivity/resistance in CRC is uncertain. In particular, the significance of ABCG2 cellular localization needs to be established. Data concerning ABCG2 mRNA expression and prediction of adjuvant irinotecan efficacy are still sparse and need to be confirmed.

Efficacy and safety of neoadjuvant chemotherapy with oxaliplatin, 5-fluorouracil, and levofolinate for T3 or T4 stage II/III rectal cancer: the FACT trial

PURPOSE

A multicenter phase II clinical study was performed in patients with T3 or T4 stage II/III rectal cancer to evaluate the efficacy and safety of neoadjuvant chemotherapy with 5-fluorouracil, levofolinate, and oxaliplatin (mFOLFOX6).

METHODS

Patients received four 2-week cycles of mFOLFOX6 therapy (oxaliplatin at 85 mg/m² + leucovorin at 200 mg/m² + fluorouracil as a 400 mg/m² bolus followed by infusion of 2400 mg/m² over 46 h, all on Day 1). They were evaluated by computed tomography after completion of the fourth cycle. If there was no disease progression, two additional cycles were administered and then surgery was performed. Adjuvant chemotherapy was generally administered for 6 months using appropriate regimens at the discretion of the physician.

RESULTS

mFOLFOX6 therapy was given to 52 patients with locally advanced rectal cancer. The preoperative response rate was 48.8% and the operation rate was 80.8%. Serious adverse events of Grade 3-4 were neutropenia (n = 5), leukopenia (n = 1), thrombocytopenia (n = 1), febrile neutropenia (n = 1), nausea (n = 1), vomiting (n = 1), and peripheral neuropathy (n = 2). The R0 resection rate, pathologic complete response rate, and sphincter preservation rate were 91.0, 11.9, and 73.8%, respectively. Postoperative complications were tolerable.

CONCLUSIONS

The present results suggested that neoadjuvant therapy with mFOLFOX6 is safe and effective, representing a reasonable treatment option for locally advanced rectal cancer.

Tumor profiling of co-regulated receptor tyrosine kinase and chemoresistant genes reveal different targeting options for lung and gastroesophageal cancers

The expression of a number of genes can influence the response rates to chemotherapy while genes encoding receptor tyrosine kinases (RTKs) determine the response to most targeted cancer therapies currently used in clinics. In this study, we evaluated seven genes known to influence chemotherapeutic response (ERCC1, BRCA1, RRM1, TUBB3, STMN1, TYMS, and TOP2A) and five RTKs (EGFR, ERBB2, PDGFRB, VEGFR1 and VEGFR2) in non-small cell lung cancer (NSCLC) and esophagus cancer (EC) and the data are compared to gastric cancer (GC) data reported previously. We demonstrate significant differences in the expression profiles between different cancer types as well as heterogeneity among patients within the same cancer type. In all three cancer types, five chemoresistant genes (TOP2A, STMN1, TYMS, BRCA1 and RRM1) are coordinately up-regulated in almost all EC, approximately 90% of NSCLC and one third of GC patients. Most EC and nearly half of GC patients have increased expression of the three RTKs critical to angiogenesis (PDGFR, VEGFR1 and VEGFR2), while almost none of the NSCLC patients have elevated expression of angiogenic RTKs. A variable percentage of patients in the three cancer types show upregulation of the EGFR family RTKs, EGFR and/or ERBB2. It is of interest to note that approximately 10% of the NSCLC and GC patients are triple-negative for the chemosensitivity genes, angiogenic and EGFR RTK genes. The results suggest significant gene expression differences between different cancer types as well as heterogeneity within each cancer type and therefore different molecules should be targeted for future drug development and clinical trials.

ABCG2 expression in colorectal adenocarcinomas may predict resistance to irinotecan

Irinotecan is a key drug for patients with advanced and recurrent colorectal carcinoma. However, the efficacy of irinotecan is not sufficient; partly, as there is no useful marker to predict chemosensitivity to the drug. The aim of the present study was to evaluate whether the expression levels of adenosine triphosphate-binding cassette sub-family G (WHITE) member 2 (Junior blood group) (ABCG2) in primary colorectal tumors predict chemoresistance to irinotecan. Using the resected primary tumor specimens of 189 patients with colorectal cancer, the association between the immunohistochemical expression of ABCG2 protein and the results of the collagen gel droplet embedded culture drug sensitivity test, performed to evaluate the chemosensitivity to SN-38 (an active metabolite of irinotecan), was investigated. Among the 189 patients, 17 received irinotecan-based chemotherapy, and their responses and progression-free survival (PFS) were analyzed. The tumors of patients with increased ABCG2 expression accounted for 60% of the tumors examined, and were significantly more resistant to SN-38, compared with patients with low ABCG2 expression (P<0.001). In a multivariate logistic regression analysis, increased expression of ABCG2 protein was an independent and significant predictor of resistance to SN-38, increasing the risk of resistance by 12-fold. Increased expression of ABCG2 and a low sensitivity to SN-38 was significantly associated with resistance to irinotecan-based chemotherapy (P=0.01 and 0.028, respectively). The median PFS of patients with increased expression of ABCG2 was significantly shorter, compared with patients with low expression levels of ABCG2 (104 vs. 242 days; P=0.047). The increased immunohistochemical expression of ABCG2 in primary tumors may be a useful predictive biomarker of resistance to irinotecan-based chemotherapy for patients with recurrent or metastatic colorectal cancer.

Delineation of gastric cancer subtypes by co-regulated expression of receptor tyrosine kinases and chemosensitivity genes

Chemotherapy plays a key role in improving disease-free survival and overall survival of gastric cancer (GC); however, response rates are variable and a non-negligible proportion of patients undergo toxic and costly chemotherapeutic regimens without a survival benefit. Several studies have shown the existence of GC subtypes which may predict survival and respond differently to chemotherapy. It is also known that the expression level of chemotherapy-related and target therapy-related genes correlates with response to specific antitumor drugs. Nevertheless, these genes have not been considered jointly to define GC subtypes. In this study, we evaluated seven genes known to influence chemotherapeutic response (ERCC1, BRCA1, RRM1, TUBB3, STMN1, TYMS and TOP2A) and five receptor tyrosine kinases (RTKs) (EGFR, ERBB2, PDGFRB, VEGFR1 and VEGFR2). We demonstrate significant heterogeneity of gene expression among GC patients and identified four GC subtypes using the expression profiles of eight genes in two co-regulation groups: chemosensitivity (BRCA1, STMN1, TYMS and TOP2A) and RTKs (EGFR, PDGFRB, VEGFR1 and VEGFR2). The results are of immediate translational value regarding GC diagnostics and therapeutics, as many of these genes are curently widely used in relevant clinical testing.

Prognostic impact of membranous ATP-binding cassette Sub-family G member 2 expression in patients with colorectal carcinoma after surgical resection

ATP-binding cassette sub-family G member 2 (ABCG2) is a transporter protein that has been associated with multidrug resistance and poor prognosis in several types of cancers. In colorectal cancers, however, the prognostic value of ABCG2 expression is not yet clear. ABCG2 expression was analyzed by immunohistochemistry using tissue microarrays in 234 consecutive patients who underwent surgical resection. The ABCG2 expression level was defined by the composite score, determined by multiplying intensity and percentage of tumor staining scores. This was dichotomized at the median, and the association of ABCG2 expression with disease severity and patient survival was determined. ABCG2 expression in the cytoplasm and membrane was observed in 77.8% and 61.5% of the samples, respectively. High expression of ABCG2 in both the cytoplasm and membrane was found more frequently in well-differentiated lesions (P < 0.05). High expression of membranous ABCG2 was significantly associated with better overall survival (hazard ratio [HR], 0.624; 95% confidence interval [CI], 0.411-0.948; P = 0.027) and disease-specific survival (HR, 0.499; 95% CI, 0.308 - 0.808; P = 0.005) compared to low expression. However, cytoplasmic expression of ABCG2 was not significantly associated with patient survival. The expression level of membranous ABCG2 in colorectal tumors can predict post-operative patient survival, suggesting the potential for ABCG2 as a prognostic biomarker.

Prognostic implication of mucinous histology in colorectal cancer patients treated with adjuvant FOLFOX chemotherapy

Background:

There have been controversies in prognostic impact of mucinous histology on colorectal cancer, and its implication in patients treated with adjuvant 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) is unclear.

Methods:

Stage II and III colorectal cancer patients who underwent curative resection followed by adjuvant FOLFOX were included. Patients were grouped according to the mucinous content: >50%, mucinous adenocarcinoma (MAC); <50%, adenocarcinoma with intermediated mucinous component (AIM); and without any mucinous component, non-MAC (NMA). Clinicopathological features and disease-free survival (DFS) were compared.

Results:

Among a total of 521 patients, 27 patients (5.2%) had MAC, 41 patients (7.9%) had AIM, and 453 patients (86.9%) had NMA. Mucinous adenocarcinoma and AIM had higher frequency of proximal location and microsatellite instability, but lower frequency of angiolymphatic invasion. Disease-free survival was significantly worse in the MAC compared with NMA (3-year DFS 57% and 86%, respectively; P<0.001) and AIM (3-year DFS 87%, P=0.01 vs MAC). Multivariate analysis revealed MAC as an independent negative prognostic factor of DFS (adjusted hazard ratio 7.96, 95% confidence interval 3.76–16.8).

Conclusion:

Adenocarcinoma with intermediated mucinous component and MAC have distinct clinicopathological features compared with NMA. Mucinous adenocarcinoma has an adverse prognostic impact on stage II or III colorectal cancer treated with adjuvant FOLFOX.

Mucinous histology of colon cancer predicts poor outcomes with FOLFOX regimen in metastatic colon cancer

Mucinous adenocarcinoma (MA) of colorectal cancer seems associated with reduced responsiveness to chemotherapy. The overexpression of markers of resistance to fluorouracil and oxaliplatin has recently been demonstrated. We revised the outcomes of metastatic MA of the colon treated with FOLFOX. From January 2002 to December 2009, we treated 198 patients with metastatic colon cancer, of which 21 (10.6%) had diagnosis of MA and were compared with 42 control patients with non-mucinous adenocarcinoma (NMA). In MA group, three patients [14%; inhibitory concentration 95: ± 7.5%] reached partial response, and in NMA group, two patients obtained complete response and 16 obtained partial response with an overall response rate of 43% (inhibitory concentration 95: ± 7.6%) with a significant statistical difference (P = 0.027). Median progression-free survival for MA group was 4 months with respect to 8 months for NMA (P = 0.0001); regarding overall survival, we registered a median of 8 months with respect to 18 months for MA and NMA (P = 0.001). In multivariate analysis, MA histology, Eastern Cooperative Oncology Group performance status 2, more than two metastatic sites, and peritoneal metastatic involvement resulted in negative independent prognostic factors. Also in our study, MA is connected to poor prognosis and reduced activity of chemotherapy. In the absence of randomised studies, it may be convenient to analyse this subgroup of patients within the large trials carried out on colorectal cancer.

Immunohistochemistry of colorectal carcinoma: current practice and evolving applications

The relatively high incidence of adenocarcinoma of the colon and rectum (colorectal carcinoma) in the general population makes its pathologic diagnosis one of the more frequent exercises in anatomical pathology. Although typically mundane in the primary setting, the correct identification of metastatic colorectal carcinoma or exclusion of metastatic disease from carcinoma arising in other anatomical foci can be problematic. The advent of targeted therapies and refinement of more traditional cytotoxic chemotherapeutic regimens mandates not only a more confident appraisal of site of origin but also assessment of those tumor-specific features that may alter therapeutic decisions. Despite the exponential increase in our understanding of the molecular pathogenesis of colorectal carcinoma, immunohistochemistry remains the foundation for resolution of these problematic cases and the number of antibodies available to the practicing pathologist continues to expand at a steady rate. In some cases, immunohistochemistry may also provide valuable prognostic information, either independently or as a surrogate marker for a specific route of carcinogenesis such as microsatellite instability. This review will focus on the use of new and more established immunohistochemistry markers in the diagnosis of colorectal carcinoma, with an emphasis on aberrant staining patterns of the various colorectal carcinoma subtypes as well as the utility of these markers in specific differential diagnostic settings.

Risk factors for adverse outcome in low rectal cancer

AIM: To demonstrate the oncologic outcomes of low rectal cancer and to clarify the risk factors for survival, focusing particularly on the type of surgery performed.

METHODS: Data from patients with low rectal carcinomas who underwent surgery, either sphincter-preserving surgery (SPS) or abdominoperineal resection (APR), at The First Affiliated Hospital of Sun Yat-sen University in China from August 1994 to December 2005 were retrospectively analyzed.

RESULTS: Of 331 patients with low rectal cancer, 159 (48.0%) were treated with SPS. A higher incidence of positive resection margins and a higher 5-year cumulative local recurrence rate (14.7% vs 6.8%, P = 0.041) were observed in patients after APR compared to SPS. The five-year overall survival (OS) was 54.6% after APR and 66.8% after SPS (P = 0.018), and the 5-year disease-free survival (DFS) was 52.9% after APR and 65.5% after SPS (P = 0.013). In multivariate analysis, poor OS and DFS were significantly related to positive resection margins, pT3-4, and pTNM III-IV but not to the type of surgery.

CONCLUSION: Despite a higher rate of positive resection margins after APR, the type of surgery was not identified as an independent risk factor for survival.

Mucinous adenocarcinomas: poor prognosis in metastatic colorectal cancer

PURPOSE

Mucinous histology of metastatic colorectal cancer (CRC) has been associated with poor prognosis, however this has never been assessed in large well-defined study populations treated with the current used systemic agents. We investigated the prognostic value of mucinous histology in two large phase III studies in metastatic CRC.

PATIENTS AND METHODS

The study population included 1010 metastatic CRC patients who were treated with chemotherapy and targeted therapies in two phase III studies. Patients were classified according to the histology of the primary tumour in mucinous adenocarcinomas (MC) and non-mucinous adenocarcinomas (AC).

RESULTS

Patients with MC (n=99) were older, had more often a normal serum lactate dehydrogenase (LDH), extrahepatic localisation of metastases, larger primary tumour diameter and a higher T classification compared to patients with AC (n=911). A deficient mismatch repair system and BRAF mutations were observed in 17% and 22% of patients with MC, compared to 3% and 7% in patients with AC, respectively. Clinical outcome was investigated in both studies separately, showing a worse overall survival (OS), progression free survival and overall response rate in patients with MC compared to patients with AC. Patients with MC received less cycles of treatment compared to AC, but did not suffer from a higher incidence of grade 3/4 toxicity. In multivariate analysis, mucinous histology was as an independent negative prognostic factor for OS, resulting in a combined hazard ratio of 1.78 (95%confidence interval (CI) 1.35-2.35).

CONCLUSIONS

Patients with metastatic mucinous CRC have distinct clinicopathological features and poor response to chemotherapy and targeted agents. The strong negative prognostic value of MC warrants the use of this pathological feature as a stratification factor for clinical trials in metastatic CRC.

Clinical implications of acellular mucin pools in resected rectal cancer with pathological complete response to neoadjuvant chemoradiation

AIM

Approximately 20% of rectal cancers treated with neoadjuvant chemoradiation achieve a pathological complete response (pCR), which is associated with an improved oncological outcome. However, in a proportion of patients with a pCR, acellular pools of mucin are present in the surgical specimen. The aim of this study was to evaluate the clinical implications of acellular mucin pools in patients with rectal adenocarcinoma achieving a pCR after neoadjuvant chemoradiation followed by proctectomy.

METHOD

A single-centre colorectal cancer database was searched for patients with clinical Stage II and Stage III rectal adenocarcinoma who achieved a pCR (i.e. ypT0N0M0) after neoadjuvant chemoradiation followed by proctectomy between 1997 and 2007. Patients were categorized according to the presence or absence of acellular mucin pools in the resected specimen, and groups were compared. Patient demographics, tumour and treatment characteristics, and oncological outcomes were recorded. Primary outcomes were 3-year local and distant recurrences, and disease-free and overall survivals.

RESULTS

Two hundred and fifty-eight patients with clinical Stage II or Stage III rectal adenocarcinoma were treated by neoadjuvant chemoradiation. Fifty-eight of these patients had a 58 pCR. Eleven of the 58 patients with a pCR had acellular mucin pools in the surgical specimen. The median follow up was 40 months. The groups were statistically similar with respect to demographics, chemoradiation regimens, distance of tumour from the anal verge, clinical stage and surgical procedure. No patient had local recurrence. Patients with acellular mucin pools had increased distant recurrence (21%vs 5%), decreased disease-free survival (79%vs 95%) and decreased overall survival (83%vs 95%) rates, although none of these differences was statistically significant.

CONCLUSION

The presence of acellular mucin pools in a proctectomy specimen with a pCR does not affect local recurrence, but may suggest a more aggressive tumour biology.

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.

Impact of breast cancer resistance protein on cancer treatment outcomes

Breast cancer resistance protein (BCRP/ABCG2) was discovered in multidrug resistant breast cancer cells having an ATP-dependent transport-based resistance phenotype. This ABC transporter functions (at least in part) as a xenobiotic protective mechanism for the organism: in the gut and biliary tract, it prevents absorption and enhances elimination of potentially toxic substances. As a placental barrier, it protects the fetus; similarly, it serves as a component of blood-brain and blood-testis barrier; BCRP is expressed in stem cells and may protect them from potentially harmful agents. Therefore, BCRP could influence cancer outcomes by (a) endogenous BCRP affecting the absorption, distribution, metabolism, and elimination of anticancer drugs; (b) BCRP expression in cancer cells may directly cause resistance by active efflux of anticancer drugs; (c) BCRP expression in cancer cells could be a manifestation of the activity of metabolic and signaling pathways that impart multiple mechanisms of drug resistance, self-renewal (stemness), and invasiveness (aggressiveness)--i.e. impart a poor prognosis--to cancers. This chapter presents a synopsis of translational clinical studies relating BCRP expression in leukemias, lymphomas, and a variety of solid tumors with clinical outcome. Data are emerging that expression of BCRP, like P-glycoprotein/ABCB1, is associated with adverse outcomes in a variety of human cancers. Whether this adverse prognostic effect results from resistance imparted to the cancer cells as the direct result of BCRP efflux of anticancer drugs, or whether BCRP expression (and also Pgp expression - coexpression of these transporters is common among poor risk cancers) serves as indicators of the activity of signaling pathways that enhance cancer cellular proliferation, metastases, genomic instability, enhance drug resistance, and oppose programmed cell death mechanisms is yet unknown.

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.

Effect of mucin production on survival in colorectal cancer: a case-control study

AIM

To investigate the impact of mucin production on prognosis in colorectal cancer, in terms of overall survival (OS) and time to disease progression (TTP) in patients with mucinous compared to those with non-mucinous colorectal cancer (NMCRC), matched for age, gender, and tumor stage.

METHODS

Thirty five patients with mucinous colorectal cancer (MCRC) were matched for age, gender, and tumor stage with 35 controls having NMCRC. OS and TTP were compared among 4 groups divided according to mucin content: group A (50%-75% mucin), group B (75%-100% mucin), group C or controls (<50% mucin). Group D consisted of all patients with tumors having <75% mucin (controls and groups A together).

RESULTS

Median survival in MCRC and NMCRC groups was 46.2 and 112.9 mo, respectively (P=0.26). OS in groups A and B was 70.1 and 32.8 mo (P=0.46), and in groups B and D was 32.8 and 70.1 mo, respectively (P=0.143). TTP in MCRC and NMCRC was 50.17 and 44.77 mo, respectively (P=0.795). TTP in groups A, B, and D was 70.1, 24.8, and 65.5 mo, respectively. Twenty-eight percent of patients with MCRC had poorly differentiated adenocarcinoma versus 8.6% in NMCRC patients (P=0.028).

CONCLUSION

MCRC is associated with a non-significant decrease in median survival and TTP, particularly when mucin content is >75% of tumor volume. However, it tends to be more poorly differentiated. A larger study matching for stage and grade is needed.

Mucinous colorectal adenocarcinoma: influence of mucin expression (Muc1, 2 and 5) on clinico-pathological features and prognosis

BACKGROUND

Mucinous component is associated with distinct clinical and pathological features and poor survival in colorectal cancer. The purpose of this study was to determine differences in outcomes of patients with mucinous colorectal adenocarcinoma according to the type of mucin expressed.

MATERIALS AND METHODS

Immunohistochemistry was performed in all tumors of patients who underwent radical surgery between 1998 and 2003 with mucinous colorectal cancer using antibodies against MUC1, 2, and 5. Correlation between immunoexpression and clinical, pathological features and survival was performed.

RESULTS

Of the 418 patients treated in this period, only 35 had a mucinous adenocarcinoma. Of these, 25 were positive for 1 or more mucin expression. MUC2 expression correlated with tumor site and depth of penetration, while MUC5 expression correlated to tumor site. Overall survival was significantly worse for patients with MUC2 expression, and disease-free survival was significantly worse for patients with MUC1 expression.

CONCLUSIONS

Mucin expression may have significant correlation to specific clinical-pathological features and survival of patients with mucinous-type colorectal adenocarcinoma. These differences may reflect distinct molecular mechanisms involved in carcinogenesis of mucinous colorectal adenocarcinoma.

ABCG2: determining its relevance in clinical drug resistance

Multidrug resistance is a major obstacle to successful cancer treatment. One mechanism by which cells can become resistant to chemotherapy is the expression of ABC transporters that use the energy of ATP hydrolysis to transport a wide variety of substrates across the cell membrane. There are three human ABC transporters primarily associated with the multidrug resistance phenomenon, namely Pgp, MRP1, and ABCG2. All three have broad and, to a certain extent, overlapping substrate specificities, transporting the major drugs currently used in cancer chemotherapy. ABCG2 is the most recently described of the three major multidrug-resistance pumps, and its substrates include mitoxantrone, topotecan, irinotecan, flavopiridol, and methotrexate. Despite several studies reporting ABCG2 expression in normal and malignant tissues, no trials have thus far addressed the role of ABCG2 in clinical drug resistance. This gives us an opportunity to critically review the disappointing results of past clinical trials targeting Pgp and to propose strategies for ABCG2. We need to know in which tumor types ABCG2 contributes to the resistance phenotype. We also need to develop standardized assays to detect ABCG2 expression in vivo and to carefully select the chemotherapeutic agents and clinical trial designs. This review focuses on our current knowledge about normal tissue distribution, tumor expression profiles, and substrates and inhibitors of ABCG2, together with lessons learned from clinical trials with Pgp inhibitors. Implications of SNPs in the ABCG2 gene affecting the pharmacokinetics of substrate drugs, including many non-chemotherapy agents and ABCG2 expression in the SP population of stem cells are also discussed.

Inhibition of G1/S transition potentiates oxaliplatin-induced cell death in colon cancer cell lines

In a series of colorectal cancer cell lines, both necrosis and apoptosis were induced upon exposure to oxaliplatin, and enhanced by co-administration of the Hsp90 inhibitor 17-AAG. We analyzed the effects of these interventions on the cell cycle, and found that oxaliplatin treatment caused G1 and G2 arrest in HCT116 cells, and S-phase accumulation in two p53-deficient cell lines (HT29 and DLD1). Addition of 17-AAG enhanced cell cycle effects of oxaliplatin in HCT116, and induced G1 arrest and decrease in S-phase population in the other cell lines. Analysis of cell cycle proteins revealed that the major difference between the cell lines was that in HCT116, 17-AAG resulted in profound inhibition of expression and phosphorylation of late G1 proteins cyclin E and cdk2, with no effect on p21/WAF1 induction. Consistent with these, an HCT116 p53(-/-) line, lacking p21, showed resistance to oxaliplatin, failure to enter apoptosis, and an accumulation of cells in S-phase. Introduction of p21 in these cells caused reversal of that phenotype, including restoration of the G1 block and re-sensitization to oxaliplatin. Inhibition of G1/S progression using cdk2 inhibitor also enhanced oxaliplatin cytotoxicity. We conclude that in colon cancer cells with impaired p53 function, interventions directed to cycle arrest in G1 may potentiate oxaliplatin activity.

Colorectal carcinoma associated with serrated adenoma--prevalence, histological features, and prognosis

Serrated adenoma has been proposed to be a distinct entity among colorectal neoplasms. Progression to frank carcinoma has been suggested in individual cases, but the prevalence of carcinomas originating from serrated adenomas and their clinico-pathological characteristics are not known. In the present study, a large series of colorectal cancers was analysed for the occurrence of serrated adenoma in association with carcinoma and clinico-pathological features were compared in cases with and without serrated adenoma. Specimens from 466 colorectal carcinoma patients undergoing operations between 1986 and 1996 were re-evaluated for the presence of juxtaposed serrated adenoma and carcinoma. Clinico-pathological features such as location, Dukes' stage, histological grade, mucinous differentiation, and prognosis were evaluated. Twenty-seven carcinomas (5.8%) were found in association with an adjacent serrated adenoma. Eight of the patients were male and 19 were female. All of these adenocarcinomas showed a serrated appearance resembling that of serrated adenomas. Nine (33%) cases were mucinous and a mucinous component was present in 11 (41%) additional cases. The majority of the tumours were located either in the caecum (14 cases; 51%) or in the rectum (9 cases; 33%). DNA microsatellite instability was more common in carcinomas associated with serrated adenoma (37.5%) than in other carcinomas (11.0%). It is concluded that carcinoma associated with serrated adenoma is a distinct type of colorectal neoplasm, accounting for 5.8% of all colorectal carcinoma cases in this study. Predilection for the caecum and the rectum may reflect their aetiological factors. Female preponderance is contrary to that reported for hyperplastic polyps and serrated adenomas.