Colorectal carcinoma: diagnostic, prognostic, and molecular features

Colorectal cancer with liver metastases: Neoadjuvant chemotherapy, surgical resection first or palliation alone?

Colorectal cancer (CRC) is one of the commonest cancers with 1.2 million new cases diagnosed each year in the world. It remains the fourth most common cause of cancer-related mortality in the world and accounts for > 600000 cancer-related deaths each year. There have been significant advances in treatment of metastatic CRC in last decade or so, due to availability of new active targeted agents and more aggressive approach towards the management of CRC, particularly with liver-only-metastases; however, these drugs work best when combined with conventional chemotherapy agents. Despite these advances, there is a lack of biomarkers to inform us about the accurate management of the patients with metastatic CRC. It is therefore imperative to carefully select the patients with comprehensive multi-disciplinary team input in order to optimise the management of these patients. In this review we will discuss various treatment options available in management of colorectal liver metastases with potential guidance on how and when to choose these options along with consideration on future directions in management of this disease.

Local excision of T1 and T2 rectal cancer: proceed with caution

AIM

This study aimed to compare the clinical outcome between local excision (LE) and total mesorectal excision (TME) for early rectal cancer.

METHOD

After Institutional Review Board approval, charts of patients with T1 or T2 N0M0 rectal adenocarcinoma treated by curative LE or TME without preoperative radiotherapy from 2004 to 2012 were reviewed. Categorical and continuous variables were compared using chi-square analysis and the ANOVA test. Kaplan-Meier analysis compared survival rates.

RESULTS

The study included 153 patients: 79 underwent TME and 74 LE. Postoperative infection was more common after TME (P = 0.009). There was tumour involvement of the margins in 13.5% after LE compared with 0% after TME (P = 0.001). Of the patients treated initially by LE, 13.5% had additional surgery for unfavourable histological findings and 4.1% had residual tumour. Median follow up was 35 (17-96) months. No deaths were recorded in 56 patients with a pT1 lesion. There was no significant difference in local recurrence (P = 0.332) or 3-year disease-free survival (DFS; P = 0.232) between patients having LE or TME. The 68 patients with a T2 lesion had higher local recurrence (P = 0.025) and lower DFS following LE compared with TME (P = 0.044). There was no difference in overall survival (P = 0.351).

CONCLUSION

LE of early rectal cancer is associated with higher local recurrence and decreased DFS. These disadvantages are significant for T2 lesions.

CpG island methylator phenotype and prognosis of colorectal cancer in Northeast China

Purpose. To investigate the association between CpG island methylator phenotype (CIMP) and the overall survival of sporadic colorectal cancer (CRC) in Northeast China. Methods. 282 sporadic CRC patients were recruited in this study. We selected MLH1, MGMT, p16, APC, MINT1, MINT31, and RUNX3 as the CIMP panel markers. The promoter methylation was assessed by methylation sensitive high resolution melting (MS-HRM). Proportional hazards-regression models were fitted with computing hazard ratios (HR) and the corresponding 95% confidence intervals (95% CI). Results. 12.77% (36/282) of patients were CIMP-0, 74.1% (209/282) of patients were CIMP-L, and 13.12% (37/282) of patients were CIMP-H. The five-year survival of the 282 CRC patients was 58%. There was significant association between APC gene promoter methylation and CRC overall survival (HR = 1.61; 95% CI: 1.05–2.46; P = 0.03). CIMP-H was significantly associated with worse prognosis compared to CIMP-0 (HR = 3.06; 95% CI: 1.19–7.89; P = 0.02) and CIMP-L (HR = 1.97; 95% CI: 1.11–3.48; P = 0.02), respectively. While comparing with the combine of CIMP-L and CIMP-0 (CIMP-L/0), CIMP-H also presented a worse prognosis (HR = 2.31; 95% CI: 1.02–5.24; P = 0.04). Conclusion. CIMP-H may be a predictor of a poor prognosis of CRC in Northeast China patients.

LGR5 regulates survival through mitochondria-mediated apoptosis and by targeting the Wnt/β-catenin signaling pathway in colorectal cancer cells

Colorectal cancer (CRC) is one of the most common causes of cancer-related death worldwide. The leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) is a newly identified surface marker of colorectal cancer stem cells (CSCs). Expression level of LGR5 is commonly elevated in human CRCs. Our previous study demonstrated that the elevated expression of LGR5 is associated with CRC initiation and progression. However, the role of LGR5 in CRC pathogenesis has not been sufficiently established. In this study, we aimed to characterize the role of LGR5 in CRC pathogenesis using the loss-of-function approach. Depletion of LGR5 suppressed the growth of several cultured CRC cells and caused an increase in the fraction of apoptotic cells, which were analyzed using Annexin V/PI staining and DNA fragmentation assay. Furthermore, depleting LGR5 induced apoptosis through the loss of mitochondrial membrane potential. Additionally, depletion of LGR5 suppressed β-catenin nuclear translocation and blocked the activity of Wnt/β-catenin signaling as manifested in the reduced expression of c-myc and cyclin D, two Wnt/β-catenin targets in CRC cells. Treatment with Wnt3a considerably alleviated the growth inhibition and apoptotic cell death induced by LGR5 depletion in CRC cells. These data suggested that LGR5 regulates cell proliferation and survival by targeting the Wnt/β-catenin signaling pathway. Thus, the findings of this study suggest that LGR5 plays a vital role in CRC pathogenesis and has the potential to serve as a diagnostic marker and a therapeutic target for CRC patients.

Analysis of 116 cases of rectal cancer treated by transanal local excision

BACKGROUND

The purpose of this research was to evaluate the therapeutic effects and prognostic factors of transanal local excision (TAE) for rectal cancer.

METHODS

We retrospectively analyzed 116 cases that underwent TAE for rectal cancer from 1995 to 2008. A Cox regression analysis was used to analyze prognostic factors.

RESULTS

The survival times for the patients were from 14 to 160.5 months (median time, 58.5 months). The 5-year and 10-year overall survival rates were 72% and 53%, respectively. In all 16 cases experienced local recurrence (13.8%). Pathological type, recurrence or metastasis, and depth of infiltration (T stage) were the prognostic factors according to the univariate analysis, and the latter two were independent factors affecting patient prognosis. For patients with T1 stage who underwent adjuvant radiotherapy, there was no local recurrence; for those in T2 stage, the local recurrence rate was 14.6%. In addition, there was no difference between the patients who received radiotherapy and those who did not (T1: P = 0.260, T2: P = 0.262 for survival rate and T1: P = 0.480, T2: P = 0.560 for recurrence).

CONCLUSIONS

The result of TAE for rectal cancer is satisfactory for T1 stage tumors, but it is not suitable for T2 stage tumors.

Tumour budding is a reproducible index for risk stratification of patients with stage II colon cancer

AIM

High-risk patients with Stage II colon cancer may benefit from adjuvant chemotherapy, but it is difficult to identify such a patient group. A robust and reproducible index would be helpful to select the subset of Stage II colon cancer patients at high risk. This study investigated the potential prognostic significance of tumour budding in Stage II colon cancer.

METHOD

In all, 135 Stage II colon cancer patients with known outcome were identified. The degree of tumour budding was assessed by two individual observers and was classified, according to the number of tumour buds in the area with the greatest budding intensity on haematoxylin and eosin slides, as high-grade budding (10 or more tumour buds) and low-grade budding (0-9 buds). Inter-observer agreement for two observers was assessed by using the kappa test. Progression-free and cancer-specific survivals were analysed using the Kaplan-Meier method and Cox regression.

RESULTS

The 5-year progression-free survival rates for patients with high-grade tumour budding (n = 36) and those with low-grade budding (n = 99) were 57.6% and 89.0% (P < 0.001). The 5-year cancer-specific survival rates were 66.7% vs 92.0% (P < 0.001). Cox regression analyses demonstrated tumour budding as an independent predictor of disease progression (hazard ratio 4.982, P < 0.001) and cancer-related death (hazard ratio 4.142, P = 0.003). The two observers agreed on the classification of tumour budding in 118 cases (87.4%) and the inter-observer agreement was good (κ = 0.692).

CONCLUSION

Tumour budding is a strong and reproducible prognostic factor for adverse outcome in Stage II colon cancer, which may serve as a prognostic marker to identify patients with a high risk of recurrence who may benefit from adjuvant therapy.

Mismatch repair system and p53 expression in patients with T1 and T2 colorectal cancer: predictive role of lymph node metastasis and survival

BACKGROUND

The aim of this study was to evaluate the predictive role of the mismatch repair (MMR) system and p53 expression for lymph node metastasis and long-term survival in patients with T1 and T2 colorectal cancer.

METHODS

A total of 543 patients with T1 or T2 colorectal cancers who underwent radical surgery with regional lymphadenectomy from December 2007 to December 2009 were analyzed. Predictive factors for lymph node metastasis and prognostic factors were analyzed.

RESULTS

During the median follow-up period of 4 years, the 5-year disease-free survival rate for patients without lymph node metastasis was 94.8%, which was significantly higher than that for those with lymph node metastases (85.2%; P < 0.001). On multivariate analysis, gender, tumor location, N category, lymphatic invasion, vascular invasion, and perineural invasion were independent prognostic factors for disease-free survival; however MMR defect, p53 expression, and microsatellite instability (MSI) were not. The presence of lymphatic invasion, vascular invasion, and tumor budding were independent predictors of lymph node metastasis.

CONCLUSIONS

In patients with T1 or T2 colorectal cancer, lymphatic invasion, vascular invasion, and tumor budding were predictive of lymph node metastasis; however, MMR defect, p53 expression, and MSI were not predictive.

Characterization of perineural invasion as a component of colorectal cancer staging

Perineural invasion (PN) in colorectal cancer (CRC) is a site-specific prognostic marker, as mentioned by the AJCC Cancer Staging Manual, but it remains to be clearly defined. We aimed to identify an optimal characterization of PN as a component of cancer staging. On the basis of the anatomic features of the nervous system of the large bowel, site-specific pathologic criteria were assigned to PN according to the location of PN. Multi-institutional pathologic review based on these criteria was performed for 962 patients with stage I to III CRC at 2 institutions (1999 to 2004, cohort 1) and 1883 patients from 8 other institutions (2000 to 2004, cohort 2). In cohort 1, intramural and extramural PN were observed in 152 and 101 patients, respectively, which had a different impact on disease-free survival (hazard ratio, 2.6 [1.9 to 3.5] vs. 4.7 [3.4 to 6.5], respectively). A 3-tiered grading system (Pn0; Pn1a, intramural PN; Pn1b, extramural PN) distinguished 5-year disease-free survival as 88%, 70%, and 48%, respectively; and multivariate analysis identified PN grade as a significant prognostic marker independent of T or N stage. These results were similar in cohort 2. Interinstitutional difference of the prognostic impact of PN grade was acceptably small among all institutions. Interobserver study among 6 gastrointestinal pathologists showed superior judgment reproducibility for PN compared with vascular invasion. The results of our study indicate that PN is an important prognostic marker in CRC. The value of cancer staging could be enhanced by PN assessment using site-specific criteria and a simple grading system based on PN location within the bowel.

Need for objective and reproducible criteria in histopathological assessment of total mesorectal excision specimens: lessons from a national improvement project

AIM

Data on quality control of the pathologic evaluation of total mesorectal excision (TME) specimens are scarce. We aimed to assess differences between evaluation by local pathologists participating in PROject on CAncer of the REctum (PROCARE; a Belgian improvement project on rectal cancer) and by a review panel of experts.

METHOD

Based on photographic material and histopathology slides, a Review Committee of gastrointestinal expert pathologists re-evaluated the mesorectal plane, the tumour differentiation grade, the (y)pT stage and the tumour regression grade in 444 patients previously routinely assessed by local pathologists.

RESULTS

The surgical plane was reported in 89% of patients and the circumferential resection margin in 88% of patients by the local pathologist. The median number of lymph nodes harvested in patients undergoing neoadjuvant radiochemotherapy was 11 and 14 in the other patients. The Review Committee downgraded the surgical plane from (intra)mesorectal to intramuscular in 17% of patients, and upgraded it from intramuscular to (intra)mesorectal in 27%. Tumour differentiation grade, T stage and tumour regression grade differed between local pathologists and the Review Committee in 15%, 10% and 38%, respectively, of patients. T stage was upgraded, mainly from T2 to T3, in 8% of patients. Tumour regression was judged by the Review Committee to be less advanced in 15% of patients.

CONCLUSION

Acknowledging some shortcomings, this study gives a realistic view of clinical practice. There are differences in interpretation with regard to both macroscopic and microscopic analysis of TME specimens. These findings indicate a need for more objective and reproducible criteria in histopathology. Being aware of this is a first step for improvement.

Peritoneal elastic lamina invasion: limitations in its use as a prognostic marker in stage II colorectal cancer

Peritoneal involvement in colorectal cancer (CRC) is an adverse prognostic feature, which may prompt consideration of adjuvant chemotherapy in stage II disease. Controversies and challenges surrounding its assessment have led to consideration of peritoneal elastic lamina invasion (ELI) as an alternative marker of advanced local spread. The objectives of this study were (1) to evaluate the prognostic significance of peritoneal ELI in stage II CRC and (2) to determine the feasibility of ELI assessment in routine practice with the use of an elastic stain. Two hundred seventeen patients with stage II CRC (186, pT3; 31, pT4) were assessed for ELI and other established adverse histologic features. Of the pT3 tumors, 31 (16.7%) were ELI positive, 121 (65%) were ELI negative, and 34 (18.3%) lacked an identifiable elastic lamina. There were no significant differences in disease-free survival between pT3 ELI-negative and ELI-positive tumors (P = .517). The disease-free survival of pT4 tumors was significantly lower than that of pT3 ELI-negative tumors (P = .024) and pT3 ELI-positive tumors (P = .026), respectively. The elastic lamina was detected less frequently in right-sided pT3 tumors compared with left-sided tumors (65/91 [71.4%] versus 87/95 [91.6%], P < .001). Right-sided tumors were also associated with a reduction in the staining intensity of the elastic lamina (P < .001). In conclusion, peritoneal ELI was not an adverse prognostic factor in this study. The frequent absence of an identifiable elastic lamina, particularly in right-sided tumors, may limit the use of ELI as a prognostic marker in CRC.

Methylene blue-assisted lymph node dissection technique is not associated with an increased detection of lymph node metastases in colorectal cancer

Lymph node staging is of paramount importance for prognosis estimation and therapy stratification in colorectal cancer. A high number of harvested lymph nodes is associated with an improved outcome. Methylene blue-assisted lymph node dissection effectively improves the lymph node harvest and ensures sufficient staging. Now, the effect on node positivity rate and stage-related outcome was investigated. The study cohort with advanced lymph node dissection consisted of 669 colorectal cancer cases of all stages, which were collected between 2007 and 2012. A historical collection of 663 cases investigated with conventional techniques between 2002 and 2004 served as control. Lymph node harvest was dramatically improved in the study group with mean lymph node numbers of 34 ± 17 vs 13 ± 5 (P<0.001) and sufficient staging rates of 98% vs 62% (P<0.001). However, neither the rate of nodal positive cases (37% vs 37%; P = 0.98) nor the rate of N2 cases differed between the two groups (14% vs 13%; P = 0.80). Furthermore, no differences were found concerning the outcome in both groups. The advanced lymph node dissection technique guarantees adequate histopathological lymph node staging in virtually all cases of colorectal cancer and is therefore extremely helpful. The hypothesis that it also provides a higher sensitivity in detecting metastases, however, could be not proved.

DEK over expression as an independent biomarker for poor prognosis in colorectal cancer

BACKGROUND

The DEK protein is related to chromatin reconstruction and gene transcription, and plays an important role in cell apoptosis. High expression levels of the human DEK gene have been correlated with numerous human malignancies. This study explores the roles of DEK in tumor progression and as a prognostic determinant of colorectal cancer.

METHODS

Colorectal cancer specimens from 109 patients with strict follow-up, and colorectal adenomas from 52 patients were selected for analysis of DEK protein by immunohistochemistry. The correlations between DEK over expression and the clinicopathological features of colorectal cancers were evaluated by Chi-square test and Fisher's exact tests. The survival rates were calculated by the Kaplan-Meier method, and the relationship between prognostic factors and patient survival was also analyzed by the Cox proportional hazard models.

RESULTS

DEK protein showed a nuclear immunohistochemical staining pattern in colorectal cancers. The strongly positive rate of DEK protein was 48.62% (53/109) in colorectal cancers, which was significantly higher than that in either adjacent normal colon mucosa (9.17%, 10/109) or colorectal adenomas (13.46%, 7/52). DEK over expression in colorectal cancers was positively correlated with tumor size, grade, lymph node metastasis, serosal invasion, late stage, and disease-free survival- and 5-year survival rates. Further analysis showed that patients with late stage colorectal cancer and high DEK expression had worse survival rates than those with low DEK expression. Moreover, multivariate analysis showed high DEK expression, serosal invasion, and late stage are significant independent risk factors for mortality in colorectal cancer.

CONCLUSIONS

DEK plays an important role in the progression of colorectal cancers and it is an independent poor prognostic factor of colorectal cancers.

Prognostic significance of lymphovascular or perineural invasion in patients with locally advanced colorectal cancer

BACKGROUND

This study was designed to evaluate the prognostic significance of the positivity of lymphovascular (LVI) and perineural invasion (PNI) in patients with locally advanced colorectal cancer.

METHODS

From January 1999 to December 2009, 1,437 consecutive patients who underwent curative surgery for stage II or III colorectal cancer were analyzed. Patients were then categorized into 4 groups: LVI-/PNI- (n = 850), LVI+ only (n = 178), PNI+ only (n = 271), and LVI+/PNI+ (n = 138).

RESULTS

With a median follow-up period of 56 months, the 5-year overall survival rates of patients with LVI-/PNI-, LVI+ only, PNI+ only, and LVI+/PNI+ were 82%, 73%, 71%, and 56%, respectively (P < .001), and the 5-year disease-free survival rates of patients with LVI-/PNI-, LVI+ only, PNI+ only, and LVI+/PNI+ were 80%, 70%, 65%, and 46%, respectively (P < .001). In multivariate analysis, LVI+/PNI+ was an independent prognostic factor for both overall survival (P < .001) and disease-free survival (P < .001).

CONCLUSIONS

Positivity of both LVI and PNI is a strong predictor of overall and disease-free survival in patients with stages II and III colorectal cancer.

Novel drug discovery opportunities for colorectal cancer

INTRODUCTION

Colorectal cancer (CRC) is a leading cause of cancer mortality worldwide, with > 1.2 million new cases and > 600,000 deaths per year. This complex disease is driven by multiple genetic lesions, commonly dysregulated signaling pathways, and aberrant activity of developmental programs such as Notch and Wnt. While emerging therapies such as EGFR inhibitors are improving treatment regimens, recent findings elucidating the role of cancer stem cells provide insights into opportunities for novel therapeutic intervention.

AREAS COVERED

This review provides a background on CRC statistics, colon anatomy and CRC pathobiology, CRC genetics and current and emerging therapies. Furthermore, the article discusses the role of developmental signaling pathways governing self-renewal biology as potential points for therapeutic intervention.

EXPERT OPINION

Despite recent advances including the introduction of targeted therapeutics, prognosis for advanced CRC patients remains bleak, reinforcing the need for novel therapeutic intervention. Developmental pathways such as Notch and Wnt provide opportunities to address this urgent need, and preclinical evidence supports targeting these pathways in CRC. Progress has been made toward this end, and while challenges persist, an increasing number of preclinical findings show promise.

Preoperative carcinoembryonic antigen as an outcome predictor in colon cancer

OBJECTIVE

Several reports have shown that certain pre-operative CEA intervals can be predictive of long-term outcomes and have subsequently implied that preoperative CEA may be useful to assess the risk of recurrence or death as a continuous number for individual cases. This analysis assesses if this hypothesis is valid after correction for confounders.

METHODS

All colon cancer patients operated on at Massachusetts General Hospital from 2004 through 2011 were considered for retrospective review. Association between outcomes and preoperative CEA was measured in intervals and as a linear relationship.

RESULTS

Of the 1,071 patients operated for colon adenocarcinoma, 621 (57.9%) had a preoperative CEA drawn and were included in the analysis. In models using intervals, preoperative CEA did show association with (disease-free) survival, but this was shown to be chiefly a surrogate for metastatic presentation. In linear approaches adjusted for metastatic presentation, CEA loses all correlations with metastatic disease (P = 0.84), survival (P = 0.11), survival duration (P = 0.42) and disease-free interval (P = 0.94).

CONCLUSIONS

Extrapolating the predictive value of certain preoperative CEA intervals to a continuous approach for use in a case-for-case basis is unjustified. Preoperative CEA may be a useful risk estimator but has limited significance for predictions of long-term outcomes in individual cases.

CXCR4 Expression and Treatment with SDF-1α or Plerixafor Modulate Proliferation and Chemosensitivity of Colon Cancer Cells

BACKGROUND

Signaling through stromal cell-derived factor-1α (SDF-1α), strongly secreted by bone marrow stromal cells and the CXC chemokine receptor 4 (CXCR4) exposed on tumor cells has pivotal roles in proliferation, metastasis, and tumor cell "dormancy." Dormancy is associated with cytostatic drug resistance and is probably a property of tumor stem cells and minimal residual disease. Thus, hampering the SDF-1α/CXCR4 cross talk by a CXCR4 antagonist like Plerixafor (AMD3100) should overcome tumor cell dormancy bymobilization of tumor cells from "sanctuary" niches. Our aim was to elucidate the direct effects exerted by SDF-1α and Plerixafor on proliferation, chemosensitivity, and apoptosis of CXCR4-expressing tumor cells.

METHODS

The ability of SDF-1α and Plerixafor to regulate intracellular signaling, proliferation, and invasion was investigated using two colon cancer cell lines (HT-29 and SW480) with either high endogenous or lentiviral expression of CXCR4 compared to their respective low CXCR4-expressing counterparts as a model system. Efficacy of Plerixafor on sensitivity of these cell lines against 5-fluorouracil, irinotecan, or oxaliplatin was determined in a cell viability assay as well as stroma-dependent cytotoxicity and apoptosis assays.

RESULTS

SDF-1α increased proliferation, invasion, and ERK signaling of endogenously and lentivirally CXCR4-expressing cells. Exposure to Plerixafor reduced proliferation, invasion, and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling. Combination of chemotherapy with Plerixafor showed an additive effect on chemosensitivity and apoptosis in CXCR4-overexpressing cells. An SDF-1-secreting feeder layer provideda"protective niche" for CXCR4-overexpressing cells resulting in decreased chemosensitivity.

CONCLUSION

CXCR4-antagonistic therapy mobilizes and additionally sensitizes tumor cells toward cytoreductive chemotherapy.

Acid-mediated tumour cell invasion: a discrete modelling approach using the extended Potts model

Acidic extracellular pH has been shown to play a crucial part in the invasive and metastatic cascade of some tumours. In this study, we examine the effect of extracellular acidity on tumour invasion focusing, in particular, on cellular adhesion, proteolytic enzyme activity and cellular proliferation. Our numerical simulations using a cellular Potts model show that, under acidic extracellular pH, changes in cell-matrix adhesion strength has a comparable effect on tumour invasiveness as the increase in proteolytic enzyme activity. We also show that tumour cells cultured under physiological pH tend to be large and the tumours develop a "diffuse" morphology compared to those cultured at acidic pH, which display protruding "fingers" at the advancing front. A key model prediction is the observation that the main effect on invasion from culturing cells at low extracellular pH stems from changes in the intercellular and cell-matrix adhesion strengths and proteolytic enzyme secretion rate. However, we show that the effects of proteolysis needs to be significant as low to moderate changes only has nominal effects on cell invasiveness. We find that the low pH e effects on cell size and proliferation rate have much lower influence on cell invasiveness.

Elevated ALCAM shedding in colorectal cancer correlates with poor patient outcome

Molecular biomarkers of cancer are needed to assist histologic staging in the selection of treatment, outcome risk stratification, and patient prognosis. This is particularly important for patients with early-stage disease. We show that shedding of the extracellular domain of activated leukocyte cell adhesion molecule (ALCAM) is prognostic for outcome in patients with colorectal cancer (CRC). Previous reports on the prognostic value of ALCAM expression in CRC have been contradictory and inconclusive. This study clarifies the prognostic value of ALCAM by visualizing ectodomain shedding using a dual stain that detects both the extracellular and the intracellular domains in formalin-fixed tissue. Using this novel assay, 105 patients with primary CRCs and 12 normal mucosa samples were evaluated. ALCAM shedding, defined as detection of the intracellular domain in the absence of the corresponding extracellular domain, was significantly elevated in patients with CRC and correlated with reduced survival. Conversely, retention of intact ALCAM was associated with improved survival, thereby confirming that ALCAM shedding is associated with poor patient outcome. Importantly, analysis of patients with stage II CRC showed that disease-specific survival is significantly reduced for patients with elevated ALCAM shedding (P = 0.01; HR, 3.0), suggesting that ALCAM shedding can identify patients with early-stage disease at risk of rapid progression.

Plastin3 is a novel marker for circulating tumor cells undergoing the epithelial-mesenchymal transition and is associated with colorectal cancer prognosis

Circulating tumor cells (CTC) in blood have attracted attention both as potential seeds for metastasis and as biomarkers. However, most CTC detection systems might miss epithelial-mesenchymal transition (EMT)-induced metastatic cells because detection is based on epithelial markers. First, to discover novel markers capable of detecting CTCs in which EMT has not been repressed, microarray analysis of 132 colorectal cancers (CRC) from Japanese patients was conducted, and 2,969 genes were detected that were overexpressed relative to normal colon mucosa. From the detected genes, we selected those that were overexpressed CRC with distant metastasis. Then, we analyzed the CRC metastasis-specific genes (n = 22) to determine whether they were expressed in normal circulation. As a result, PLS3 was discovered as a CTC marker that was expressed in metastatic CRC cells but not in normal circulation. Using fluorescent immunocytochemistry, we validated that PLS3 was expressed in EMT-induced CTC in peripheral blood from patients with CRC with distant metastasis. PLS3-expressing cells were detected in the peripheral blood of approximately one-third of an independent set of 711 Japanese patients with CRC. Multivariate analysis showed that PLS3-positive CTC was independently associated with prognosis in the training set (n = 381) and the validation set [n = 330; HR = 2.17; 95% confidence interval (CI) = 1.38-3.40 and HR = 3.92; 95% CI = 2.27-6.85]. The association between PLS3-positive CTC and prognosis was particularly strong in patients with Dukes B (HR = 4.07; 95% CI = 1.50-11.57) and Dukes C (HR = 2.57; 95% CI = 1.42-4.63). PLS3 is a novel marker for metastatic CRC cells, and it possesses significant prognostic value.

Elastic laminal invasion in colon cancer: diagnostic utility and histological features

Primary tumors of the colorectal cancers are assessed pathologically based on the tumor spread into the bowel wall. The assessment of serosal involvement, which may be relevant to pT4, can be challenging for pathologists, making the consistency of diagnoses questionable. As solutions to this problem, the following two strategies could be adopted. One would be to use special staining or immunohistochemical staining techniques for diagnostic assistance. The other would be to construct recommendations for the assessment of tumor spreading and to obtain a world-wide consensus on the criteria used to assess tumor spreading. Using elastic staining, we previously reported that peritoneal elastic laminal invasion (ELI) could be objectively determined and would likely contribute to a simplified and more objective stratification of deep tumor invasion around the peritoneal surface. We also noted the importance of sampling, staining, and histo-anatomical knowledge in the application of elastic staining during routine pathological diagnosis. Here we review the history of primary tumor stratification leading to the present TNM classification and report on the current status of pathological assessments made at our hospital to summarize what has been established and what is further required for the pathological diagnosis of tumor spreading in patients with colorectal cancer.

The Correlation between Microsatellite Instability and the Features of Sporadic Colorectal Cancer in the North Part of Iran

Background. The aim of this study was to determine the correlation between MSI and sporadic colorectal cancer in Guilan province, North part of Iran. Materials and Methods. A total of 96 patients who underwent resection for sporadic colorectal cancer in Guilan province were studied. No patients had positive family history of cancers. The frequencies of MSI were analyzed by testing the BAT-26 and BAT-25 markers. Results. MSI analysis revealed that 22.9% of the tumors (22 patients) were microsatellite instability positive and 77.1% (74 patients) were microsatellite instability negative. The highest rate of MSI (40.9%) was found in the rectal region. MSI-H status was seen more frequently in distal tumors (P = 0.04, odds ratio = 3.13, 0.96–10.14). Conclusions. Distal tumor location and MSI may associate with special clinicopathological features. It seems that there may be correlation with underlying genetic and immunologic mechanisms.

Lgr5 is a potential marker of colorectal carcinoma stem cells that correlates with patient survival

BACKGROUND

Lgr5 (leucine-rich-repeat-containing G-protein-coupled receptor 5) has recently been identified as an intestinal stem cell marker. In order to determine whether Lgr5 is a potential marker of cancer stem cells, we investigated whether Lgr5 expression correlated with Ki-67 expression and prognosis in colorectal carcinoma.

METHODS

Lgr5 and Ki-67 expression were evaluated by immunohistochemistry in 192 colorectal carcinoma specimens. Selection of side population (SP) cells was performed by staining with Hoechest 33342, and Lgr5 expression in Colo205 SP cells was then detected by immunofluorescence.

RESULTS

Lgr5 expression was significantly higher in carcinoma than in normal mucosa (P=0.001). Lgr5 was positively correlated with histological grade (P=0.001), depth of invasion (P=0.001), lymph node metastasis (P=0.001), distant metastasis (P=0.004), pTNM stage (P=0.001), and Ki-67 (r=0.446, P=0.001). Multivariate analysis showed that the effect of Lgr5 on survival was independent of Ki-67 (P=0.037). In the in vitro study, Hoechst low-staining cells were counted in 7% of the Colo205 colon cancer cell line population, and Lgr5 expression was strikingly stronger in Hoechst low-staining cells than in high-staining cells (P=0.001).

CONCLUSIONS

These findings suggest that Lgr5 may play an important role in the progression and prognosis of colorectal carcinoma, and may be a potential new therapeutic target for the treatment of colorectal cancer patients. It may also be considered as a potential marker for colorectal cancer stem cells (CSCs).

Lgr5 is a potential marker of colorectal carcinoma stem cells that correlates with patient survival

Background

Lgr5 (leucine-rich-repeat-containing G-protein-coupled receptor 5) has recently been identified as an intestinal stem cell marker. In order to determine whether Lgr5 is a potential marker of cancer stem cells, we investigated whether Lgr5 expression correlated with Ki-67 expression and prognosis in colorectal carcinoma.

Methods

Lgr5 and Ki-67 expression were evaluated by immunohistochemistry in 192 colorectal carcinoma specimens. Selection of side population (SP) cells was performed by staining with Hoechest 33342, and Lgr5 expression in Colo205 SP cells was then detected by immunofluorescence.

Results

Lgr5 expression was significantly higher in carcinoma than in normal mucosa (P=0.001). Lgr5 was positively correlated with histological grade (P=0.001), depth of invasion (P=0.001), lymph node metastasis (P=0.001), distant metastasis (P=0.004), pTNM stage (P=0.001), and Ki-67 (r=0.446, P=0.001). Multivariate analysis showed that the effect of Lgr5 on survival was independent of Ki-67 (P=0.037). In the in vitro study, Hoechst low-staining cells were counted in 7% of the Colo205 colon cancer cell line population, and Lgr5 expression was strikingly stronger in Hoechst low-staining cells than in high-staining cells (P=0.001).

Conclusions

These findings suggest that Lgr5 may play an important role in the progression and prognosis of colorectal carcinoma, and may be a potential new therapeutic target for the treatment of colorectal cancer patients. It may also be considered as a potential marker for colorectal cancer stem cells (CSCs).

Prognostic and predictive value of circulating tumor cell analysis in colorectal cancer patients

Objective

The aim of this study was to assess the prognostic and predictive values of circulating tumor cell (CTC) analysis in colorectal cancer patients.

Patients and methods

Presence of CTCs was evaluated in 60 colorectal cancer patients before systemic therapy - from which 33 patients were also evaluable for CTC analysis during the first 3 months of treatment - through immunomagnetic enrichment, using the antibodies BM7 and VU1D9 (targeting mucin 1 and EpCAM, respectively), followed by real-time RT-PCR analysis of the tumor-associated genes KRT19, MUC1, EPCAM, CEACAM5 and BIRC5.

Results

Patients were stratified into groups according to CTC detection (CTC negative, when all marker genes were negative; and CTC positive when at least one of the marker genes was positive). Patients with CTC positivity at baseline had a significant shorter median progression-free survival (median PFS 181.0 days; 95% CI 146.9-215.1) compared with patients with no CTCs (median PFS 329.0 days; 95% CI 299.6-358.4; Log-rank P < .0001). Moreover, a statistically significant correlation was also founded between CTC detection during treatment and radiographic findings at the 6 month staging. This correlation applied to CTC results before therapy (odds ratio (OR), 6.22), 1 to 4 weeks after beginning of treatment (OR, 5.50), 5 to 8 weeks after beginning of treatment (OR, 7.94) 9 to 12 weeks after beginning of treatment (OR, 14.00) and overall CTC fluctuation during the course of treatment (OR, 20.57).

Conclusion

The present study provides evidence of a strong correlation between CTC detection and radiographic disease progression in patients receiving chemotherapy for colorectal cancer. Our results suggest that in addition to the current prognostic factors, CTC analysis represent a potential complementary tool for prediction of colorectal cancer patients’ outcome. Moreover, the present test allows for molecular characterization of CTCs, which may be of relevance to the creation of personalized therapies.

The clinical significance of lymph node size in colon cancer

To date, the clinical value of lymph node size in colon cancer has been investigated only in a few studies. Only in radiological diagnosis is lymph node size routinely recognized, and nodes ≥10 mm in diameter are considered pathologic. However, the few studies regarding this topic suggest that lymph node size is not a reliable indicator of metastatic disease. Moreover, we hypothesized that increasing lymph node size is associated with favorable outcome. By performing a morphometric study, we investigated the clinical significance of lymph node size in colon cancer in terms of metastatic disease and prognosis. A cohort of 237 cases with excellent lymph node harvest (mean lymph node count: 33±17) was used. The size distribution in node-positive and -negative cases was almost identical. In all, 151 out of the 305 metastases detected (49.5%) were found in lymph nodes with diameters ≤5 mm. Only 25% of lymph nodes >10 mm showed metastases. Minute lymph nodes ≤1 mm were involved only very rarely (2 of 81 cases). In 67% of the cases, the largest positive lymph node was <10 mm. The prognostic relevance of lymph node size was investigated in a subset of 115 stage I/II cases. The occurrence of ≥7 lymph nodes that were >5 mm in diameter was significantly associated with better overall survival. Our data show that lymph node size is not a suitable factor for preoperative lymph node staging. Minute lymph nodes have virtually no role in correct histopathological lymph node staging. Finally, large lymph nodes in stage I/II disease might indicate a favorable outcome.

Multimodal treatment strategies for locally advanced rectal cancer

This review outlines the important multimodal treatment issues associated with locally advanced rectal cancer. Changes to chemotherapy and radiation schema, as well as modern surgical approaches, have led to a revolution in the management of this disease but the morbidity and mortality remains high. Adequate treatment is dependent on precise preoperative staging modalities. Advances in staging via endorectal ultrasound, computed tomography, MRI and PET have improved pretreatment triage and management. Important prognostic factors and their impact for this disease are under investigation. Here we discuss the different treatment options including modern tumor-related surgical approaches, neoadjuvant as well as adjuvant therapies. Further clinical progress will largely depend on the broader implementation of multidisciplinary treatment strategies following the principles of evidence-based medicine.

Gelatinases A and B expression in human colorectal cancer in upper Egypt: a clinicopathological study

AIM

Prognosis of colorectal carcinoma depends on many factors, such as age and sex of patient; location; multiplicity; local extent and size of tumor, bowel obstruction, or perforation; as well as tumor microscopic type and grade; vascular and perineural invasion; and nodal and distant metastasis. The matrix metalloproteinases (MMPs) are a family of proteolytic enzymes strongly implicated in tumor invasion and metastasis, hence in tumor prognosis. The purpose of this study was to assess the role of MMP-2 and MMP-9 expression in colorectal tumorigenesis, invasion, and metastasis, hence their prognostic values.

METHOD

Immunohistochemical analysis of MMP-2 and MMP-9 in colorectal cancer cells, an immunohistochemical score based on the intensity of immunoreactivity and proportion of immunoreactive cells that established for each MMP, and correlation of this expression with the established prognostic factors.

RESULTS

MMP-2 was expressed in 81.8% (strong expression in 40%) of cases, and MMP-9 was expressed in 72% (strong expression in 35%) of cases.

CONCLUSIONS

MMP-2 and MMP-9 are widely expressed in colorectal carcinoma, suggesting significant diagnostic and prognostic values in these tumors. Increased levels of MMP-2 and MMP-9 protein expression in colorectal carcinoma tissues as compared to normal tissues suggest their association with colorectal tumor invasion and metastasis and that they could be targets for intervention and therapy in colorectal carcinoma.

Tumor budding is an independent predictor of outcome in AJCC/UICC stage II colorectal cancer

BACKGROUND

In colorectal cancer, the morphology of the invasive tumor margin may reflect aggressiveness of tumor growth, thus providing important prognostic information. The tumor growth pattern according to Jass and the extent of tumor budding were analyzed in patients with American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) stage II disease.

METHODS

Tumors of 120 randomly selected patients with AJCC/UICC stage II disease were retrospectively reviewed for tumor growth pattern (expanding vs. infiltrating) and the extent of tumor budding, with high-grade budding reflecting presence of 10 or more budding foci scattered at the invasive tumor margin. Progression-free and cancer-specific survivals were determined by the Kaplan-Meier method. For multivariable analysis, Cox's proportional hazards regression models were performed.

RESULTS

The infiltrating growth pattern was significantly associated with histological subtype and lymphovascular invasion, while high-grade budding was significantly associated with tumor grade and lymphovascular invasion. High-grade budding, but not the infiltrating growth pattern, was significantly associated with outcome in univariable analysis. Cox's proportional hazards regression models proved tumor budding to be an independent predictor of disease progression (hazard ratio 3.91, 95 % confidence interval 1.3-11.77; P = 0.02) and cancer-related death (hazard ratio 5.90, 95 % confidence interval 1.62-21.51; P = 0.007). The combination of infiltrating growth pattern and high-grade budding did not have a stronger prognostic significance than tumor budding alone.

CONCLUSIONS

Tumor budding independently predicted patient outcome in patients with AJCC/UICC stage II colorectal cancer and may therefore be used for accurate prognostication, patient counseling, and design of clinical trials by using integrated multimodal therapy.

Analysis of colorectal cancer morphology in relation to sex, age, location, and family history

BACKGROUND

Studies of colorectal cancer (CRC) have suggested different mechanisms of carcinogenesis in men and women, young and old patients, right- and left sided tumors, and sporadic and familial tumors. These differences might be reflected in morphology.

METHODS

CRCs from 1613 patients operated on in 2004-2006 in Sweden were histologically reviewed. Morphology was examined in relation to sex, age groups, location, and family history.

RESULTS

Tumors in the right colon were larger, of higher stage, more often poorly differentiated, more mucin-producing, more often had a peritumoral lymphocytic infiltrate and a high level of tumor-infiltrating lymphocytes (TILs), and more seldom had an infiltrating margin than tumors in the left colon and rectum (p < 0.0001 for most features). Young patients (<60 years) more seldom had multiple tumors but more often had perineural invasion, an infiltrative tumor margin, and high-stage tumors. Three features, TILs, medullary tumors, and invasive tumor margin, were related to sex. Only vascular invasion was related to familiality.

CONCLUSION

Location is the factor that has the most influence on tumor morphology. The results support the idea that different carcinogenic mechanisms may be involved in the right and left colon. Age is the most important determinant for the presence of multiple tumors and is a crucial factor for the aggressiveness of the disease.

Colorectal poorly differentiated neuroendocrine carcinomas and mixed adenoneuroendocrine carcinomas: insights into the diagnostic immunophenotype, assessment of methylation profile, and search for prognostic markers

Colorectal poorly differentiated neuroendocrine carcinomas (NECs) and mixed adenoneuroendocrine carcinomas (MANECs) are well-recognized entities generally known to be associated with biological aggressiveness and poor patient survival. However, a few published papers have highlighted the existence of a subgroup of tumors with a better survival than expected; however, to date, there are no established parameters that usefully identify this category. In the present study we have investigated the morphologic features, the CpG methylator phenotype (CIMP), microsatellite instability (MSI), and the immunohistochemical profile, including the expression of transcription factors (TTF1, ASH1, CDX2, and PAX5), stem cell markers (CD117 and CD34), and cytokeratins 7 and 20, in a series of 39 carcinomas (27 NECs and 12 MANECs) to better characterize such neoplasms and to search for prognostic indicators. No different patient survival was observed between NECs and MANECs. Neoplasms showed a heterogenous spectrum of morphologic and immunohistochemical features; however, only large-cell subtype, significant peritumoral lymphoid reaction, CD117 immunoreactivity, vascular invasion, and MSI/CIMP+ status were significantly correlated with prognosis on univariable analysis. Furthermore, vascular invasion and CD117 immunoreactivity were independent prognostic markers on multivariable analysis. In addition to these prognostic features, neoplasms showed different expression of transcription factors, stem cell markers, and cytokeratins that should be considered for diagnostic purposes and, especially, for discriminating among possible differential diagnoses.

The impact on clinical outcome of high prevalence of diabetes mellitus in Taiwanese patients with colorectal cancer

BACKGROUND

Both colorectal cancer (CRC) and diabetes mellitus (DM) are important public health problems worldwide. As there are controversies about survival impact on CRC patients with preexisting DM, the purpose of the present study is to evaluate the incidence and the survival impact of preexisting DM on the long-term outcomes of patients with CRC in Taiwan.

METHODS

From January 2002 to December 2008, 1,197 consecutive patients with histologically proven primary CRC, who received surgical treatment at a single institution, were enrolled. The clinicopathologic features between these patients with and without DM were retrospectively investigated. Moreover, we intended to analyze the impact of DM on overall survival (OS) and cancer-specific survival (CSS) rates.

RESULTS

Of 1,197 CRC patients, 23.6% of patients had either a reported history of DM or were currently taking one or more diabetes-controlling medications. CRC patients with DM were significantly older than those without DM (P <0.001), and had a higher incidence of cardiac disease and higher body mass index than those without DM (both P<0.001). There were no significant differences in gender, tumor size, tumor location, histological type, AJCC/UICC cancer stage, vascular invasion, perineural invasion, comorbidity of pulmonary disease or renal disease, and OS, and CSS between two groups. Additionally, DM patients had a higher incidence of second malignancy than patients without DM (9.54% vs 6.01%, P=0.040).

CONCLUSIONS

A considerably high prevalence of DM in CRC patients but no significant impact of DM on survival was observed in the single-institution retrospective study, regardless of cancer stages and tumor locations. Therefore, treatment strategies for CRC patients with DM should be the same as patients without DM.

A novel classification system for perineural invasion in noncutaneous head and neck squamous cell carcinoma: histologic subcategories and patient outcomes

OBJECTIVE

The aims of this study were to define a novel classification system of tumor perineural invasion (PNI) with respect to tumor/nerve involvement such as intratumoral (IT), peripheral, or extratumoral (ET) and to determine the prognostic significance of each of these histologic subcategories in patients with noncutaneous head and neck squamous cell carcinoma (HNSCC).

STUDY DESIGN

This study is a retrospective chart review and histologic analysis of patients with HNSCC in the setting of a tertiary care medical center.

METHODS

A clinical chart review of 142 patients with HNSCC who underwent primary surgical treatment from January 2004 through December 2007 was performed. Clinical information collected included patient age, sex, alcohol and tobacco use, tumor location, TNM stage, postoperative adjuvant chemotherapy and/or radiation treatment, and patient outcome. For each case, PNI density, the distance of each PNI focus to the tumor edge, and size of the largest nerve involved were measured. Furthermore, PNI was subcategorized as IT, peripheral, or ET. A Cox regression analysis was performed to determine if PNI was related to regional disease recurrence. Kaplan-Meier survival analysis was also performed.

RESULTS

Among the 142 patients, 37 (26%) had disease progression. The maximum extent of PNI was significantly correlated with disease-free survival on multivariate analysis (P = .019) and was also significantly related to disease-free survival when T stage (P = .017), N stage (P = .021), and T and N stages (P = .02) were added to the Cox regression model. Kaplan-Meier analysis demonstrated a trend toward increased disease-free survival of PNI negative and IT/peripheral PNI compared with ET PNI.

CONCLUSION

Perineural invasion is correlated with nodal status and T stage and is related to disease-free survival. It can be subcategorized as IT, peripheral, or ET. This novel classification system has important implications with regard to clinical outcome and may help define a cohort of patients that may require more aggressive management.

ARNTL2 and SERPINE1: potential biomarkers for tumor aggressiveness in colorectal cancer

PURPOSE

Cathepsin and plasmin may favor cancer cell invasion degrading extracellular matrix. Plasmin formation from plasminogen is regulated by plasminogen activator inhibitor type-1 (PAI-1). ARNTL2 activates the promoters of the PAI-1 gene, officially called SERPINE1, driving the circadian variation in circulating PAI-1 levels.

METHODS

We evaluated ARNTL2 and SERPINE1 expression in 50 colorectal cancer specimens and adjacent normal tissue and in colon cancer cell lines.

RESULTS

We found up-regulation of ARNTL2 (P = 0.004) and SERPINE1 (P = 0.002) in tumor tissue. A statistically significant association was found between high ARNTL2 mRNA levels and vascular invasion (P < 0.0001), and between high SERPINE1 mRNA levels and microsatellite instability (MSI-H and MSI-L, P = 0.025). Sorting the subjects into quartile groups, a statistically significant association was found between high ARNTL2 expression and lymph node involvement (P < 0.001), between high SERPINE1 expression and grading (P < 0.001) and between high SERPINE1 expression and MSI H-L (P < 0.0001). In SW480 cells, a more proliferative model compared to CaCo2 cells, there were higher mRNA levels of ARNTL2 (P < 0.001) and SERPINE1 (P = 0.001).

CONCLUSION

ARNTL2 and SERPINE1 expression is increased in colorectal cancer and in a highly proliferative colon cancer cell line and is related to tumor invasiveness and aggressiveness.

Mucinous differentiation in colorectal cancer--indicator of poor prognosis?

AIMS

  To analyse the prognostic impact of mucinous differentiation in colorectal mucinous adenocarcinomas and adenocarcinomas with a mucinous component.

METHODS AND RESULTS

  A total of 381 tumours were reviewed for mucinous differentiation by two independent pathologists. Mismatch repair status was assessed by immunohistochemistry. Prognostic significance was assessed by univariate and multivariate analyses. Eighty-one (21%) tumours were Union Internationale Contre le Cancer (UICC) Stage I, 120 (31%) Stage II, 126 (33%) Stage III and 54 (14%) Stage IV. Mucinous adenocarcinomas accounted for 12% and adenocarcinomas with a mucinous component for 19% of tumours. Mucinous differentiation was associated significantly with mismatch repair protein deficiency. The presence of extracellular mucin, regardless of extent, did not affect patients' outcome, while tumour grade, vascular and perineural invasion, tumour border configuration and budding were associated significantly with outcome. Cox analysis proved venous invasion to be an independent predictor of outcome in mucinous adenocarcinomas and both venous invasion and tumour budding as independent predictors of outcome in adenocarcinomas with any amount of mucin.

CONCLUSIONS

  Mucinous adenocarcinomas and/or adenocarcinomas with mucinous component do not differ from conventional adenocarcinomas with respect to prognosis and histological predictors of outcome. Hence, recording of mucinous differentiation may be used as an indicator of mismatch repair deficiency, but not for prognostic stratification.

Localization of nerve fibers in colonic polyps, adenomas, and adenocarcinomas by immunocytochemical staining for PGP 9.5

BACKGROUND

PGP 9.5 is a cytoplasmic protein and is a specific marker for neurites and neurons.

AIMS

Using anti-PGP 9.5, this study aimed to localize nerve fibers in normal colons, polyps, adenomas and adenocarcinomas.

METHODS

Colonic polyps, adenomas and T(1) to T(3) adenocarcinomas with adjacent normal colon were immunostained for PGP 9.5 using rabbit anti-PGP 9.5.

RESULTS

In normal colon, numerous nerve fibers were localized in inner and outer muscles, from which submucosa and lamina propria were innervated. In hyperplastic polyps and tubular adenomas, the stalk revealed Meissner's plexus and large-diameter nerve fibers, and fine nerve fibers innervated abundantly in lamina propria of hyperplastic polyps and small tubular adenomas. In villous adenomas, large-diameter nerve fibers and Meissner's plexus were localized in the stalk whereas a few or no fine nerve fibers were localized in fine stroma. In adenocarcinomas, more fine fibers were localized in submucosal stroma adjacent to the invading carcinoma in T(1) carcinomas but there were no nerve fibers in the midst of tumors in T(2) and T(3) carcinomas. There were focally and sporadically increased nerve fibers adjacent to invading cancer nests in 5 of 8 T(2) cases. In T(3) carcinomas, fragmented Auerbach's plexus were noted in cancer-invaded colonic muscles and there were no increased fine nerve fibers in the cancer-invaded subserosa in the majority of cases. PGP 9.5 immunostaining revealed tumor-associated neurogenesis in submucosa but no obviously increased nerve fibers within cancer-invaded muscles.

CONCLUSIONS

This lack of tumor-associated neurogenesis supports insidious and often silent clinical presentation of colonic carcinomas until invading through the colonic wall to adjacent organs.

K-ras mutations are correlated to lymph node metastasis and tumor stage, but not to the growth pattern of colon carcinoma

In colorectal carcinoma, pathological assessment of tumors is essential for determining therapy and prognosis of the disease. Molecular associations of tumor complexity index and genetic alternations can be helpful to understand the tumor progression mechanism. Oncogenic K-ras is one of the major colorectal cancer associated genes, and is mutated in up to 50% of colorectal cancers. In this current study, we correlated tumor complexity index with mutations in K-ras codon 12, 13, and 61 in association with different clinicopathological parameters such as TNM stage, localization, sex, and age. Formalin-fixed paraffin embedded tissue blocks from colon cancer samples was selected from 88 patients diagnosed with adenocarcinoma. Mutations in the K-ras gene were detected using pyrosequencing technique. Tumor complexity index was calculated using immunohistochemically stained images of the tumor outline of the specimens and then analyzing these pictures using Photoshop CS, Fovea Pro, and Image J computer programs. Statistical analysis was performed with SPSS. K-ras mutations were detected in 17 (19.3%) colon cancer samples. Most of the samples were at a lower complexity index. No correlation was observed between K-ras mutations and complexity index. However, K-ras mutations were correlated with regional lymph node metastasis and tumor stages and complexity index with tumor wall penetration. In conclusion, complexity index and K-ras mutations are independent events; however, both correlate with tumor progression and are important in the biologic development of colon carcinoma.

SOX2 expression correlates with lymph-node metastases and distant spread in right-sided colon cancer

Background

The transcription factor SOX2, which is involved in the induction of pluripotent stem cells and contributes to colorectal carcinogenesis, is associated with a poor prognosis in colon cancer (CC). Furthermore, SOX2 is a repressor of the transcriptional activity of β-catenin in vitro. Since the majority of CC develop via an activation of the Wnt/β-catenin signalling pathway, indicated by nuclear expression of β-catenin, we wanted to investigate the expression patterns of SOX2 and β-catenin and correlate them with the occurrence of lymph node and distant metastases as indicators of malignant progression.

Methods

The expression of SOX2 and β-catenin was investigated in a case control study utilizing a matched pair collection (N = 114) of right-sided CCs with either corresponding distant metastases (N = 57) or without distant spread (N = 57) by applying immunohistochemistry.

Results

Elevated protein expression of SOX2 significantly correlated with the presence of lymph node- (p = 0.006) and distant metastases (p = 0.022). Nuclear β-catenin expression correlated significantly only with distant metastases (p = 0.001). Less than 10% of cases showed a coexpression of high levels of β-catenin and SOX2. The positivity for both markers was also associated with a very high risk for lymph-node metastases (p = 0.007) and distant spread (p = 0.028).

Conclusion

We demonstrated that increased expression of either SOX2 or nuclear β-catenin are associated with distant metastases in right-sided CC. Additionally, SOX2 is also associated with lymph-node metastases. These data underline the importance of stemness-associated markers for the identification of CC with high risk for distant spread.

Perspectives on current tumor-node-metastasis (TNM) staging of cancers of the colon and rectum

Improvements in classifications of cancers based on discovery and validation of important histopathological parameters and new molecular markers continue unabated. Though still not perfect, recent updates of classification schemes in gastrointestinal oncology by the American Joint Commission on Cancer (tumor-node-metastasis [TNM] staging) and the World Health Organization further stratify patients and guide optimization of treatment strategies and better predict patient outcomes. These updates recognize the heterogeneity of patient populations with significant subgrouping of each tumor stage and use of tumor deposits to significantly "up-stage" some cancers; change staging parameters for subsets of IIIB and IIIC cancers; and introduce of several new subtypes of colon carcinomas. By the nature of the process, recent discoveries that are important to improving even routine standards of patient care, especially new advances in molecular medicine, are not incorporated into these systems. Nonetheless, these classifications significantly advance clinical standards and are welcome enhancements to our current methods of cancer reporting.

A Lentiviral CXCR4 overexpression and knockdown model in colorectal cancer cell lines reveals plerixafor-dependent suppression of SDF-1α-induced migration and invasion

BACKGROUND

The development of distant metastasis is associated with poor outcome in patients with colorectal cancer (CRC). The stromal cell-derived factor-1 (SDF-1) and its receptor CXC chemokine receptor 4 (CXCR4) have pivotal roles in the chemotaxis of migrating tumor cells during metastasis. Thus, hampering the SDF-1/CXCR4 cross-talk is a promising strategy to suppress metastasis.

METHODS

We investigated the invasive behavior of the lentivirally CXCR4 overexpressing CRC cell lines SW480, SW620 and RKO in chemotaxis and invasion assays toward an SDF-1α gradient. Low endogenous CXCR4 expression levels were determined by quantitative realtime polymerase chain reaction (PCR) and fluorescence-activated cell sorting (FACS) analyses.

RESULTS

A lentiviral CXCR4 overexpression and knockdown model was established in these CRC cells. In transwell migration assays, CXCR4 overexpression favored chemotaxis and invasion of cells in all 3 lines depending on an SDF-1α gradient (p < 0.001 vs. untransduced cells). Functional CXCR4 knockdown using lentiviral short hairpin RNA (shRNA) vectors significantly decreased the migration behavior in CRC cell lines (p < 0.001), confirming a CXCR4-specific effect. Pharmacologic inhibition of the SDF-1α/CXCR4 interaction by the bicyclam Plerixafor(TM) at 100 μM significantly abrogated CXCR4-dependent migration and invasion through Matrigel(TM) (SW480, SW620, RKO; p < 0.05).

CONCLUSION

Our results indicate that a CXCR4-antagonistic therapy might prevent tumor cell dissemination and metastasis in CRC patients, consequently improving survival.

Lymph node yield following injection of patent blue V dye into colorectal cancer specimens

AIM

The study aimed to assess whether the ex vivo injection of patent blue V dye would increase lymph node yield in operative specimens of colorectal cancer.

METHOD

A randomized controlled trial was carried out in which patients undergoing resection for colonic cancer were allocated to patent V blue or no patent blue V dye submucosal injection of the operative specimen. The number of lymph nodes found in each group was compared.

RESULTS

Between 1 January and 31 December 2008, 68 patients were randomized. Thirty-three patients received patent blue V dye and 34 did not. In the former group the median number of blue nodes identified was 11, compared with a median of 9 in the no dye group. After the application of Carnoy's solution lymph node count was 16 in each group. There was no significant difference between all these results.

CONCLUSION

Ex vivo injection of patent blue V dye submucosally in a peritumour location did not increase the lymph node count or the percentage of specimens having more than 12 lymph nodes identified.

Intramural and extramural vascular invasion in colorectal cancer: prognostic significance and quality of pathology reporting

BACKGROUND

Blood vessel invasion has been associated with poor outcome in colorectal cancer (CRC), whereas the prognostic impact of lymphatic invasion is less clear. The authors of this report evaluated venous and lymphatic invasion as potential prognostic indicators in patients with CRC focusing on lymph node-negative patients and compared routine and review pathology diagnoses.

METHODS

In total, 381 tumors from randomly selected patients were retrospectively reviewed. The presence of vascular invasion was related to disease-free and cancer-specific survival using the Kaplan-Meier method. For multivariable analysis, Cox proportional hazards regression models were performed.

RESULTS

Lymphatic invasion and venous invasion were observed in 126 patients (33%) and 87 patients (23%), respectively, and were associated significantly with tumor classification, lymph node status, American Joint Committee on Cancer/International Union Against Cancer (AJCC/UICC) disease stage, tumor differentiation, pattern of invasion, and extent of tumor budding. The detection of vascular invasion was related to the number of examined tissue blocks. Venous and lymphatic invasion proved to be significant prognostic variables in univariable and multivariable analyses. Extramural vascular involvement was of particular significance. When the analysis was restricted to patients with (AJCC/UICC) stage II disease, venous invasion, but not lymphatic invasion, was identified as an independent prognostic variable. Review pathology diagnoses differed significantly from routine diagnoses with respect to prognostic impact.

CONCLUSIONS

Venous and lymphatic invasion proved to be significant prognostic variables in patients with CRC. The detection of vascular invasion and, consequently, risk stratification of affected patients were related to the quality of pathology workup, ie, the number of examined tissue blocks. Observed differences between review and routine pathology diagnoses illustrated the need for high-quality pathology reporting and also for standardized quality control.

Review of histopathological and molecular prognostic features in colorectal cancer

Prediction of prognosis in colorectal cancer is vital for the choice of therapeutic options. Histopathological factors remain paramount in this respect. Factors such as tumor size, histological type and subtype, presence of signet ring morphology and the degree of differentiation as well as the presence of lymphovascular invasion and lymph node involvement are well known factors that influence outcome. Our understanding of these factors has improved in the past few years with factors such as tumor budding, lymphocytic infiltration being recognized as important. Likewise the prognostic significance of resection margins, particularly circumferential margins has been appreciated in the last two decades. A number of molecular and genetic markers such as KRAS, BRAF and microsatellite instability are also important and correlate with histological features in some patients. This review summarizes our current understanding of the main histopathological factors that affect prognosis of colorectal cancer.