Colorectal cancer in the adjuvant setting: perspectives on treatment and the role of prognostic factors

AKAP4, SPAG9 and NY-ESO-1 in Iranian Colorectal Cancer Patients as Probable Diagnostic and Prognostic Biomarkers

Background and objectives:

Colorectal cancer (CRC) is the most common gastrointestinal cancer and the second leading cause of cancer death in women in the world. Cancer-Testis Antigens (CTAs) are a group of tumor-associated proteins which typically are expressed in normal reproductive cells of men, but their expression in normal somatic cells is silenced. CTAs, due to their limited expression pattern, are considered as promising targets for cancer diagnosis and immuno-therapy.

Methods:

Expression of AKAP4, SPAG9 and CTAG1B genes from the CTAs family was studied in both tumor and normal tissues of 62 Iranian CRC patients by RT-PCR with the aim of finding biomarkers for early detection and anticipated progression. Statistical analysis was performed SPSS software V22.0 to assess the significance of any associations.

Results:

Elevated expression of SPAG9 and AKAP4 genes was observed in approximately 66% and 44% of tumours, respectively, as compared to adjacent non-cancerous tissues. While a significant association was found between AKAP4 gene expression and metastasis (P-value: 0.045), expression of the CTAG1B (NY-ESO-1) gene was not observed in our cases.

Conclusion:

AKAP4 and SPAG9 genes may find use as diagnostic biomarkers for CRC and AKAP4 may play an important role in progression to metastasis.

Role of Deficient Mismatch Repair in the Personalized Management of Colorectal Cancer

Colorectal cancer (CRC) represents the third most common type of cancer in developed countries and one of the leading causes of cancer deaths worldwide. Personalized management of CRC has gained increasing attention since there are large inter-individual variations in the prognosis and response to drugs used to treat CRC owing to molecular heterogeneity. Approximately 15% of CRCs are caused by deficient mismatch repair (dMMR) characterized by microsatellite instability (MSI) phenotype. The present review is aimed at highlighting the role of MMR status in informing prognosis and personalized treatment of CRC including adjuvant chemotherapy, targeted therapy, and immune checkpoint inhibitor therapy to guide the individualized therapy of CRC.

Ki-67 Expression in CRC Lymph Node Metastasis Does Not Predict Survival

Colorectal cancer is one of the most common malignancies and a leading cause of cancer death worldwide. Molecular markers may improve clinicopathologic staging and provide a basis to guide novel therapeutic strategies which target specific tumour-associated molecules according to individual tumour biology; however, so far, no ideal molecular marker has been found to predict disease progression. We tested Ki-67 proliferation marker in primary and lymph node metastasis of CRC. We observed a statistical significant difference between the positive rates of neoplastic cells positively stained by Ki-67 in both sites, with remarkable increased number of Ki-67 positive cells in primary tumor cells compared to cancer cells that invaded lymph nodes. We can speculate that the metastatic CRC in lymph node can be more resistant to the drugs that target cellular division.

Effect of Raf kinase inhibitor protein expression on malignant biological behavior and progression of colorectal cancer

The Raf kinase inhibitor protein (RKIP) is a novel metastasis suppressor. RKIP was previously found to have low expression in a colorectal cancer (CRC) patient cohort by immunohistochemistry. However, the role of RKIP in CRC remains undetermined. In the present study, immunohistochemistry was performed to compare RKIP expression between 129 paired stage II CRC and adjacent non-tumorous tissues. The correlations between clinical parameters, prognosis and RKIP expression were evaluated. To investigate the effect of RKIP on proliferation and metastasis, RKIP was overexpressed and knocked down in colon cancer cell lines. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Transwell and wound-healing assays were performed. Murine models were established to confirm the influence of RKIP on malignant tumor phenotypes in vivo. Our results showed that RKIP expression was significantly decreased in the CRC tissues compared to the adjacent non‑cancerous tissues (p<0.001) and was correlated with the risk of relapse in stage II CRC (p<0.05). Overexpression of RKIP suppressed HCT116 cell metastasis in vitro and in vivo, whereas knockdown of RKIP expression in SW480 cells and its murine model increased metastatic ability (p<0.05). No effect of RKIP on cell proliferation in CRC was observed. These data suggest that RKIP is an important metastasis-suppressor gene in CRC. The re-expression of RKIP could be a potential therapeutic target for antimetastatic strategies for CRC.

Prostate-specific membrane antigen (PSMA) immunoexpression in the neovasculature of colorectal carcinoma in Egyptian patients

In Egypt colorectal carcinoma (CRC) is the most common type of malignancy of the digestive system. Selectively inhibiting neoangiogenesis by targeting tumor-associated blood vessels is an important therapeutic strategy. Prostate specific membrane antigen (PSMA) is expressed in the tumor-associated neovasculature of most solid cancers making it an interesting therapeutic target. We thought to study the expression of PSMA in a series of CRCs in order to test for its possible use as a target for antiangiogenic cancer therapy in Egyptian patients. One hundred CRC cases were retrieved. Representative sections from each tumor were subjected to immunohistochemistry using PSMA antibodies and CD31 antibodies as reference marker. Accordingly vascular endothelial cell immunoreactivity was semiquantitatively scored. PSMA immunostaining was positive in the neovasculature of 75% of tumors. A statistically significant relation was found between PSMA immunostaining and distant metastasis as well as vascular invasion. The present findings strengthen the evidence on the potential usefulness of PSMA as a therapeutic vascular target. This study is the first to demonstrate a positive relation between PSMA expression in CRC and distant metastasis as well vascular invasion, suggesting that PSMA may play a significant role in vascular invasion and subsequent metastasis.

A Panel of Cancer Testis Antigens and Clinical Risk Factors to Predict Metastasis in Colorectal Cancer

Colorectal cancer (CRC) is the third common carcinoma with a high rate of mortality worldwide and several studies have investigated some molecular and clinicopathological markers for diagnosis and prognosis of its malignant phenotypes. The aim of this study is to evaluate expression frequency of PAGE4, SCP-1, and SPANXA/D cancer testis antigen (CTA) genes as well as some clinical risk markers to predict liver metastasis of colorectal cancer patients. The expression frequency of PAGE4, SCP-1, and SPANXA/D cancer/testis antigen (CTA) genes was obtained using reverse transcription polymerase chain reaction (RT-PCR) assay in 90 colorectal tumor samples including both negative and positive liver metastasis tumors. Statistical analysis was performed to assess the association of three studied genes and clinical risk factors with CRC liver metastasis. The frequency of PAGE4 and SCP-1 genes expression was significantly higher in the primary tumours with liver metastasis when statistically compared with primary tumors with no liver metastasis (P < 0.05). Among all clinical risk factors studied, the lymph node metastasis and the depth of invasion were statistically correlated with liver metastasis of CRC patients. In addition, using multiple logistic regression, we constructed a model based on PAGE4 and lymph node metastasis to predict liver metastasis of CRC.

Uridine Diphosphoglucuronosyl Transferase and Methylenetetrahydrofolate Reductase Polymorphisms as Genomic Predictors of Toxicity and Response to Irinotecan-, Antifolate- and Fluoropyrimidine-Based Chemotherapy

Pharmacogenetics could be a useful tool for performing tailored anticancer chemotherapy. Several polymorphisms potentially affecting enzymes responsible for metabolism, transport and mechanism of action of irinotecan, fluoropyrimidines and antifolate agents have been investigated and sometimes associated with toxicity and response. In particular, uridine diphosphoglucuronosyl transferase 1A1 (UGT1A1) enzyme is responsible for detoxification of irinotecan active metabolite, SN38. A polymorphic structure in the promoter region (UGT1A1*28) may affect irinotecan toxicity and SN38 plasma level. Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the folate cycle, presenting two common polymorphisms (677C>T and 1298 A>C) which have impact on toxicity and efficacy of methotrexate and 5-fluorouracil.

Betulinic acid inhibits colon cancer cell and tumor growth and induces proteasome-dependent and -independent downregulation of specificity proteins (Sp) transcription factors

Background

Betulinic acid (BA) inhibits growth of several cancer cell lines and tumors and the effects of BA have been attributed to its mitochondriotoxicity and inhibition of multiple pro-oncogenic factors. Previous studies show that BA induces proteasome-dependent degradation of specificity protein (Sp) transcription factors Sp1, Sp3 and Sp4 in prostate cancer cells and this study focused on the mechanism of action of BA in colon cancer cells.

Methods

The effects of BA on colon cancer cell proliferation and apoptosis and tumor growth in vivo were determined using standardized assays. The effects of BA on Sp proteins and Sp-regulated gene products were analyzed by western blots, and real time PCR was used to determine microRNA-27a (miR-27a) and ZBTB10 mRNA expression.

Results

BA inhibited growth and induced apoptosis in RKO and SW480 colon cancer cells and inhibited tumor growth in athymic nude mice bearing RKO cells as xenograft. BA also decreased expression of Sp1, Sp3 and Sp4 transcription factors which are overexpressed in colon cancer cells and decreased levels of several Sp-regulated genes including survivin, vascular endothelial growth factor, p65 sub-unit of NFκB, epidermal growth factor receptor, cyclin D1, and pituitary tumor transforming gene-1. The mechanism of action of BA was dependent on cell context, since BA induced proteasome-dependent and proteasome-independent downregulation of Sp1, Sp3 and Sp4 in SW480 and RKO cells, respectively. In RKO cells, the mechanism of BA-induced repression of Sp1, Sp3 and Sp4 was due to induction of reactive oxygen species (ROS), ROS-mediated repression of microRNA-27a, and induction of the Sp repressor gene ZBTB10.

Conclusions

These results suggest that the anticancer activity of BA in colon cancer cells is due, in part, to downregulation of Sp1, Sp3 and Sp4 transcription factors; however, the mechanism of this response is cell context-dependent.

Role of endoglin and VEGF family expression in colorectal cancer prognosis and anti-angiogenic therapies

Colorectal cancer (CRC) is one of the cancer models and most of the carcinogenic steps are presently well understood. Therefore, successful preventive measures are currently used in medical practice. However, CRC is still an important public health problem as it is the third most common cancer and the fourth most frequent cause of cancer death worldwide. Nowadays, pathologic stage is a unique and well-recognized prognostic indicator, however, more accurate indicators of the biologic behavior of CRC are expected to improve the specificity of medical treatment. Angiogenesis plays an important role in the growth and progression of cancer but its role as a prognostic factor is still controversial. Probably the most important clinical implication of tumor angiogenesis is the development of anti-angiogenic therapy. The goal of this review is to critically evaluate the role of angiogenic markers, assessed by either endoglin-related microvessel density or expression of vascular endothelial growth factor family members in the CRC setting and discuss the role of these angiogenic markers in anti-angiogenic therapies.

A clinical risk score to predict 3-, 5- and 10-year survival in patients undergoing surgery for Dukes B colorectal cancer

Background:

The prognosis of patients with Dukes stage B colorectal cancer is unpredictable and there is continuing interest in simply and reliably identifying patients at high risk of developing recurrence and dying of their disease. The aim of this study was to devise a clinical risk score to predict 3-, 5- and 10-year survival in patients undergoing surgery for Dukes stage B colorectal cancer.

Methods:

A total of 1350 patients who underwent surgery for Dukes stage B colorectal cancer between 1991 and 1994 in 11 hospitals in Scotland were included in the analysis.

Results:

On follow-up, 926 patients died of whom 479 died of their cancer. At 10 years, cancer-specific survival was 61% and overall survival was 38%. On multivariate analysis, age ⩾75 (hazard ratio (HR) 1.45, 95% confidence interval (CI) 1.15–1.82, P=0.001), emergency presentation (HR 1.59, 95% CI 1.27–1.99, P<0.001) and anastomotic leak (HR 2.17, 95% CI 1.24–3.78, P<0.01) were independently associated with cancer-specific survival in colon cancer. On multivariate analysis, only age ⩾75 (HR 1.58, 95% CI 1.14–2.18, P<0.01) was associated with cancer-specific survival in rectal cancer. Age, presentation and anastomotic leak hazards could be simply added to form a clinical risk score from 0 to 2 in colon cancer. In patients with Dukes B stage colon cancer, the cancer-specific survival at 5 years for patients with a cumulative score 0 was 81%, 1 was 67% and 2 was 63%. The cancer-specific survival rate at 10 years for patients with a clinical risk score of 0 was 72%, 1 was 58% and 2 was 53%.

Conclusion:

The results of this study, in a mature cohort, introduce a new simple clinical risk score for patients undergoing surgery for Dukes B colon cancer. This provides a solid foundation for the examination of the impact of additional factors and treatment on prediction of 3-, 5- and 10-year cancer-specific survival.

Assessment of SMAD4, p53, and Ki-67 alterations as a predictor of liver metastasis in human colorectal cancer

PURPOSE

The liver is the most common site of metastasis in patients with colorectal cancer (CRC), and this is a determinant of the prognosis. However, no reliable molecular predictors of liver metastasis have yet been identified.

METHODS

Sixty-two surgical specimens of colorectal cancer were studied. The first group included 25 patients who achieved a disease-free survival period of at least 6 years (CRC-M0), and the second group included 37 patients with synchronous (n = 22) or metachronous (n = 15) liver metastasis (CRC-M1). SMAD4, p53, and Ki-67 expression levels were assessed immunohistochemically.

RESULTS

The loss of SMAD4 expression and elevated Ki-67 expression were found significantly more frequently in CRC-M1 patients than in CRC-M0 patients (P = 0.0047 and P = 0.013, respectively). Statistically significant differences were also observed between the CRC-M0 group and the metachronous metastasis group. No difference was seen in the overexpression of p53 between the groups. A combination analysis of SMAD4 and Ki-67 revealed no cases with maintained levels of SMAD4 and a low Ki-67 expression had or developed liver metastasis.

CONCLUSION

The loss of SMAD4 expression and elevated Ki-67 expression was therefore found to significantly correlate with liver metastasis, regardless of the time of occurrence, thus indicating these factors to be predictive markers for liver metastasis in patients with CRC.

Evaluation of clinical, laboratory and morphologic prognostic factors in colon cancer

BACKGROUND

The long-term prognosis of patients with colon cancer is dependent on many factors. To investigate the influence of a series of clinical, laboratory and morphological variables on prognosis of colon carcinoma we conducted a retrospective analysis of our data.

METHODS

Ninety-two patients with colon cancer, who underwent surgical resection between January 1999 and December 2001, were analyzed. On survival analysis, demographics, clinical, laboratory and pathomorphological parameters were tested for their potential prognostic value. Furthermore, univariate and multivariate analysis of the above mentioned data were performed considering the depth of tumour invasion into the bowel wall as independent variable.

RESULTS

On survival analysis we found that depth of tumour invasion (P < 0.001; F-ratio 2.11), type of operation (P < 0.001; F-ratio 3.51) and CT scanning (P < 0.001; F-ratio 5.21) were predictors of survival. Considering the degree of mural invasion as independent variable, on univariate analysis, we observed that mucorrhea, anismus, hematocrit, WBC count, fibrinogen value and CT scanning were significantly related to the degree of mural invasion of the cancer. On the multivariate analysis, fibrinogen value was the most statistically significant variable (P < 0.001) with the highest F-ratio (F-ratio 5.86). Finally, in the present study, the tumour site was significantly related neither to the survival nor to the mural invasion of the tumour.

CONCLUSION

The various clinical, laboratory and patho-morphological parameters showed different prognostic value for colon carcinoma. In the future, preoperative prognostic markers will probably gain relevance in order to make a proper choice between surgery, chemotherapy and radiotherapy. Nevertheless, current data do not provide sufficient evidence for preoperative stratification of high and low risk patients. Further assessments in prospective large studies are warranted.

Expression profiling of angiogenic genes for the characterisation of colorectal carcinoma

The development of new blood and lymphatic vessels is a crucial event for cancer growth, metastatic spread and relapse after therapy. In this work, the expression levels of chemokines, angiogenic and angiostatic factors and their receptors were determined in paired mucosal and tumour samples of patients with colorectal carcinoma and correlated with clinical and histological parameters by advanced multivariate analyses. The most important predictors to discriminate between tumour and paired normal mucosa turned out to be the levels of expression of plexin-A1 and stromal cell-derived factor 1 (SDF-1), the former overexpressed and the latter downregulated in tumours. The levels of osteopontin and Tie-2 transcripts discriminated between the presence and absence of lymph node infiltration, the former overexpressed in the presence of infiltration whilst the latter providing a protective role. These results add support to the notion that the expression levels of selected genes involved in new blood and lymphatic vessel formation represent trustable biomarkers of tumour development and invasion and contribute to the identification of novel molecular classifiers for colorectal carcinoma.

Prognostic significance of multiple molecular markers for patients with stage II colorectal cancer undergoing curative resection

OBJECTIVE

The aim of this study was to determine whether our constructed high-sensitivity colorimetric membrane-array method could detect circulating tumor cells (CTCs) in the peripheral blood of stage II colorectal cancer (CRC) patients and so identify a subgroup of patients who are at high risk for relapse.

SUMMARY BACKGROUND DATA

Adjuvant chemotherapy is not routinely recommended in patients diagnosed with UICC stage II CRC. However, up to 30% of patients with stage II disease relapse within 5 years of surgery from recurrent or metastatic disease. The identification of reliable prognostic factors for high-risk stage II CRC patients is imperative.

METHODS

Membrane-arrays consisting of a panel of mRNA markers that included human telomerase reverse transcription (hTERT), cytokeratin-19 (CK-19), cytokeratin-20 (CK-20), and carcinoembryonic antigen (CEA) mRNA were used to detect CTCs in the peripheral blood of 194 stage II CRC patients who underwent potentially curative (R0) resection between January 2002 and December 2005. Digoxigenin (DIG)-labeled cDNA were amplified by RT-PCR from the peripheral blood samples, which were then hybridized to the membrane-array. All patients were followed up regularly, and their outcomes were investigated completely.

RESULTS

Overall, 53 of 194 (27.3%) stage II patients were detected with the expression of all 4 mRNA markers using the membrane-array method. After a median follow up of 40 months, 56 of 194 (28.9%) developed recurrence/metastases postoperatively. Univariately, postoperative relapse was significantly correlated with the depth of invasion (P < 0.001), the presence of vascular invasion (P < 0.001), the presence of perineural invasion (P = 0.048), the expression of all 4 mRNA markers (P < 0.001), and the number of examined lymph nodes (P = 0.031). Meanwhile, using a multivariate logistic regression analysis, T4 depth of tumor invasion (P = 0.013), the presence of vascular invasion (P = 0.032), and the expression of all 4 mRNA markers (P < 0.001) were demonstrated to be independent predictors for postoperative relapse. Combination of the depth of tumor invasion, vascular invasion, and all 4 mRNA markers as predictors of postoperative relapse showed that patients with any 1 positive predictor had a hazard ratio of about 27-fold to develop postoperative relapse (P < 0.001; 95% CI = 11.42-64.40). The interval between the detection of all 4 positive molecular markers and subsequently developed postoperative relapse ranged from 4 to 10 months (median: 7 months). Furthermore, the expression of all 4 mRNA markers in all stage II CRC patients, or either stage II colon or rectal cancer patients were strongly correlated with poorer relapse-free survival rates by survival analyses (all P < 0.001).

CONCLUSIONS

The pilot study suggests that the constructed membrane-array method for the detection of CTCs is a potential auxiliary tool to conventional clinicopathological variables for the prediction of postoperative relapse in stage II CRC patients who have undergone curative resection.

Adjuvant chemotherapy with 5-fluorouracil in a patient with colorectal cancer and Familial Mediterranean Fever

Colorectal cancer is a common malignancy often requiring adjuvant chemotherapy. Familial Mediterranean Fever is a chronic hereditary disease which is relatively prevalent in the Middle East and is associated with recurrent episodes of serosal, synovial or cutaneous inflammations. The aim of this paper was to describe a patient with Familial Mediterranean Fever who received fluorouracil-based adjuvant chemotherapy for colorectal cancer. A 56-year-old man with Familial Mediterranean Fever and amyloidosis was referred for evaluation and treatment following surgery for colorectal cancer. In light of his relatively young age, good general state of health and apparently well-controlled Familial Mediterranean Fever, he was treated with chemotherapy consisting of four cycles of 5-fluorouracil and leucovorin. The patient's clinical course during chemotherapy was unremarkable except for one minor attack of Familial Mediterranean Fever. The patient's follow-up was notable for periodic fluctuations in serum carcinoembryonic antigen levels, up to 4-fold of normal. The Familial Mediterranean Fever remained stable. Although our patient showed a good tolerability of treatment, the administration of chemotherapy to patients with Familial Mediterranean Fever raises several concerns. These include a potential deterioration in the Familial Mediterranean Fever status owing to chemotherapy-induced stress, the potential effect of Familial Mediterranean Fever or its treatment on the tolerability of chemotherapy and an overlapping toxicity of the drugs used to treat the two diseases. An increase in serum carcinoembryonic antigen in this setting may be related to the underlying pathophysiologic mechanism of Familial Mediterranean Fever but does not necessarily indicate disease recurrence. Clinicians should be aware of these issues considering the recent worldwide increase in colorectal cancer.

The role of chemotherapy in microsatellite unstable (MSI-H) colorectal cancer

INTRODUCTION

High-frequency microsatellite instability (MSI-H) is an alternate pathway of colorectal carcinogenesis, which accounts for 15% of all sporadic colorectal cancers. These tumours arise from mutations in the DNA mismatch repair system and thus have different responses to chemotherapeutic agents compared to microsatellite stable (MSS) cancers.

OBJECTIVE

This review aims to summarise the available literature on the responses to chemotherapy in MSI-H colorectal cancer (CRC).

RESULTS AND DISCUSSION

5 Fluorouracil (5FU) is commonly used as a chemotherapeutic agent in colon cancer and in vitro evidence shows reduced response to 5FU in MSI-H CRC. The clinical evidence is conflicting but favours a reduced response to 5FU in MSI-H CRC. Several newer agents such as COX-2 inhibitors and irinotecan are also reviewed.

CONCLUSION

Available evidence suggests that MSI-H CRC have different behaviour patterns and response to chemotherapy compared with MSS CRC.

Raf kinase inhibitor protein expression in a survival analysis of colorectal cancer patients

PURPOSE

Raf kinase inhibitor protein (RKIP) inhibits the Raf and nuclear factor kappa B signaling pathways, and suppresses metastasis in animal models. We examined whether RKIP expression in primary colorectal cancers (CRCs) correlates with the risk of metastasis and overall survival.

PATIENTS AND METHODS

RKIP expression was examined immunohistochemically in three separate cohorts: a tissue microarray containing 276 samples from human tumors and normal tissues, and retrospective studies of 268 CRC patients and 65 early-stage CRCs. Overall and metastasis-free survival rates were measured.

RESULTS

RKIP was expressed in normal epithelia but was reduced in metastatic tumors. RKIP expression in primary CRC was an independent prognostic marker for survival using multivariate Cox regression analysis (hazard ratio, 2.808; 95% CI, 1.58 to 4.96; P = .0002), independent of Dukes' stage. Patients with Dukes' C RKIP-positive tumors had similar 5-year survival rates as early-stage patients if tumors had equivalent RKIP expression levels. An independent study of early-stage CRCs confirmed that reduced RKIP expression predicted metastatic recurrence and reduced disease-free survival (hazard ratio, 4.5; 95% CI, 1.7 to 12.3; P = .003). RKIP expression was independent of sex, age, mitotic index, lymphatic and vascular invasion, depth of invasion, and tumor site, but correlated positively with apoptotic index (P = .024). Weak or loss of RKIP expression was the most significant and independent prognostic marker using a multivariate regression equation (hazard ratio, 4.5; 95% CI, 1.7 to 12.3; P = .003).

CONCLUSION

RKIP expression in primary CRCs correlates with overall and disease-free survival, and can be useful for identifying early-stage CRC patients at risk of relapse.

5-fluorouracil (5FU) treatment does not influence invasion and metastasis in microsatellite unstable (MSI-H) colorectal cancer

Microsatellite instability is a recognised pathway of colorectal carcinogenesis responsible for about 15% of all sporadic colorectal cancers. Recent evidence has suggested that these tumours may not have the same response as microsatellite stable colon cancers to 5-fluorouracil (5FU)-based chemotherapy. The response to 5FU in four microsatellite unstable (MSI-H) cell lines was examined by cell viability assays and invasion assays. Flow cytometry was used to assess the effect of 5FU on MSI-H cell lines. In vivo response to 5FU was assessed by intraperitoneal injection of 5FU or control to 80 nude mice that had received intrasplenic injections of an MSI-H cell line KM12C prior to commencing treatment. There was inhibition of cell growth in MSI-H cell lines when treated with 5FU. There was no difference in invasiveness in the MSI-H cell lines when treated with 5FU. Primary tumours formed in 27 of the untreated and 25 of the 5FU treated mice (p=NS). There was a 36% reduction in splenic weight in those mice treated with 5FU (p<0.03). Metastases formed in 5 of the untreated and 9 of the treated mice (p=0.12). 5FU treatment of MSI-H tumours results in a reduction in growth but does not result in a reduction in invasion or metastasis.

Prognostic impact of hematogenous tumor cell dissemination in patients with stage II colorectal cancer

Adjuvant chemotherapy is not routinely recommended in patients with colorectal cancer stage UICC II. Some of these patients, however, develop recurrent disease. Therefore, valid prognostic criteria are needed to identify high-risk patients who might benefit from adjuvant therapy. Disseminated tumor cells, detected in blood and bone marrow, may prove to be a valid marker, however, the prognostic relevance of these cells remains debated. In our study, we examined the prognostic significance of disseminated tumor cells in blood and bone marrow of patients with stage II colorectal cancer. Ninety patients with potentially curative (R0) resection of colorectal cancer stage II were prospectively enrolled into the study. Bone marrow and blood samples were examined for disseminated tumor cells by CK 20 RT-PCR. Patient, tumor and treatment factors were analyzed as prognostic factors. Multivariate analysis confirmed tumor cell detection in blood (hazard ratio 2.1, p = 0.03) and T-category (hazard ratio 2.2, p = 0.02) to be independent prognostic factors for relapse-free survival. Tumor cell detection in postoperative blood samples (hazard ratio 7.7, p < 0.001) and number of removed lymph nodes (hazard ratio 6.4, p < 0.001) were independent prognostic factors for disease-specific survival. Detection of circulating tumor cells in blood samples of patients with stage II colorectal cancer identifies patients with poor outcome. This finding should be confirmed by further studies and could then be used as a basis for conducting a randomized trial evaluating the effect of adjuvant chemotherapy in stage II patients.

The presence of a systemic inflammatory response predicts poorer survival in patients receiving adjuvant 5-FU chemotherapy following potentially curative resection for colorectal cancer

There is increasing evidence that the presence of a systemic inflammatory response plays an important role in survival following curative resection for colorectal cancer. The present study evaluated the relationship between C-reactive protein concentrations and survival in a cohort of patients receiving adjuvant 5-fluorouracil (5-FU) chemotherapy following potentially curative resection for colorectal cancer. In all, 222 patients undergoing potentially curative resection for colorectal cancer were studied. Of these, 50 patients received adjuvant 5-FU-based chemotherapy. Circulating concentrations of C-reactive protein were measured prior to surgery. The minimum follow-up was 15 months; the median follow-up of the survivors was 38 months. During this period 61 patients died, 32 patients of their cancer and 29 of intercurrent disease. In those patients who did not receive adjuvant chemotherapy, age (P < 0.001), Dukes stage (P < 0.05) and an elevated C-reactive protein (P < 0.01) were significantly associated with survival. In those patients who did receive adjuvant chemotherapy, an elevated C-reactive protein concentration (P < 0.01) was significantly associated with survival. The presence of a systemic inflammatory response is an independent predictor of poor outcome in patients receiving adjuvant 5-FU-based chemotherapy following potentially curative resection for colorectal cancer.

Deciphering cellular states of innate tumor drug responses

BACKGROUND

The molecular mechanisms underlying innate tumor drug resistance, a major obstacle to successful cancer therapy, remain poorly understood. In colorectal cancer (CRC), molecular studies have focused on drug-selected tumor cell lines or individual candidate genes using samples derived from patients already treated with drugs, so that very little data are available prior to drug treatment.

RESULTS

Transcriptional profiles of clinical samples collected from CRC patients prior to their exposure to a combined chemotherapy of folinic acid, 5-fluorouracil and irinotecan were established using microarrays. Vigilant experimental design, power simulations and robust statistics were used to restrain the rates of false negative and false positive hybridizations, allowing successful discrimination between drug resistance and sensitivity states with restricted sampling. A list of 679 genes was established that intrinsically differentiates, for the first time prior to drug exposure, subsequently diagnosed chemo-sensitive and resistant patients. Independent biological validation performed through quantitative PCR confirmed the expression pattern on two additional patients. Careful annotation of interconnected functional networks provided a unique representation of the cellular states underlying drug responses.

CONCLUSION

Molecular interaction networks are described that provide a solid foundation on which to anchor working hypotheses about mechanisms underlying in vivo innate tumor drug responses. These broad-spectrum cellular signatures represent a starting point from which by-pass chemotherapy schemes, targeting simultaneously several of the molecular mechanisms involved, may be developed for critical therapeutic intervention in CRC patients. The demonstrated power of this research strategy makes it generally applicable to other physiological and pathological situations.

Polo-like kinase 1 expression is a prognostic factor in human colon cancer

AIM

To clarify the expression patterns and prognostic implications of the mitotic regulator Polo-like kinase 1 (PLK1) in colon cancer.

METHODS

Expression of PLK1 was investigated by immunohistochemistry (158 cases) and immunoblotting in tissue of colon adenomas and adenocarcinomas. PLK1 expression patterns were correlated with clinicopathological parameters and patient prognosis. In addition, expression of PLK1 was evaluated by immunoblot and PCR in colon carcinoma cell lines, and coexpression of PLK1 with the proliferation marker Ki-67 was investigated.

RESULTS

Weak PLK1 expression was observed in normal colon mucosa and adenomas. In contrast, 66.7% of carcinomas showed strong expression of PLK1. Overexpression of PLK1 correlated positively with Dukes stage (P<0.001), tumor stage (P = 0.001) and nodal status (P<0.05). Additionally, PLK1 expression was a prognostic marker in univariate survival analysis (P<0.01) and had independent prognostic significance (RR = 3.3, P = 0.02) in patients with locoregional disease. Expression of PLK1 mRNA and protein was detected in all cell lines investigated. Coexpression of PLK1 and Ki-67 was observed in the majority of colon cancer cells, but a considerable proportion of cells showed PLK1 positivity without Ki-67 expression.

CONCLUSION

PLK1 is a new prognostic marker for colon carcinoma patients and may be involved in tumorigenesis and progression of colon cancer. Strategies focusing on PLK1 inhibition in vivo might therefore represent a promising new therapeutic approach for this tumor entity.

Low Levels of Insulin-Like Growth Factor Type 1 Receptor Expression at Cancer Cell Membrane Predict Liver Metastasis in Dukes’ C Human Colorectal Cancers

PURPOSE

The aim of this study was to evaluate the prognostic significance of insulin-like growth factor type 1 receptor (IGF-1R) expression in Dukes' C human colorectal cancers (CRCs).

EXPERIMENTAL DESIGN

Immunohistochemical staining for IGF-1R was done on formalin-fixed, paraffin-embedded specimens from 161 patients with curatively resected Dukes' C CRC and at least 5-year follow-up periods. We investigated the association between the levels of IGF-1R expression and the clinicopathologic parameters. To evaluate the accurate prognostic value of IGF-1R expression, we investigated two patterns of recurrence-free survival (RFS) according to the mode of recurrence, the hepatic-RFS (H-RFS), and the nonhepatic-RFS (nH-RFS). The influence of the pattern of IGF-1R immunostaining (membranous or cytoplasmic) on RFS was also estimated.

RESULTS

High (diffuse staining) and low (focal staining) levels of IGF-1R expression were found in 45 (28%) and 116 (72%) specimens, respectively. The recurrence rate was significantly higher in the latter group (49 of 116) than the former group (9 of 45; P = 0.01). H-RFS was significantly longer for the former group than the latter group (P = 0.021), whereas no difference was found in nH-RFS between the two groups (P = 0.121). In multivariate analysis, the level of IGF-1R expression was an independent factor for H-RFS (P = 0.015) as were the depth of invasion and lymph vessel invasion (P = 0.006 and 0.022, respectively). Using a combination of the level of IGF-1R expression and these two factors, the prognostic value was further increased. When IGF-1R staining patterns (membranous or cytoplasmic) were compared, membrane staining of IGF-1R possessed prognostic significance.

CONCLUSIONS

In Dukes' C CRC, focal membrane expression of IGF-1R in the primary tumor can predict a high risk of recurrence, especially liver metastasis. Understanding the mechanisms involved could lead to new therapeutic approaches for advanced CRC.

Colorectal cancer vaccines: principles, results, and perspectives

In the search for novel therapeutic approaches to treat patients with colorectal carcinoma, anticancer vaccination holds promise. A large body of preclinical and clinical evidence has demonstrated that the immune system can be polarized against malignant cells by means of several active specific immunotherapy strategies. Although no vaccination regimen can be currently recommended outside clinical trials, tumor response and immunologic findings observed in animal models and humans prompt researchers to explore further the antitumor potential of such biotherapy in an effort to reproduce in a larger set of patients the cascade of molecular events that characterizes the successful tumor immune rejection currently observed in a minority of vaccinated subjects. In this work, we summarize the principles and the main results of cancer vaccine strategies so far implemented for the treatment of patients with colorectal carcinoma. We also discuss the most recent preclinical tumor immunology insights that might change the way to design the next generation of cancer vaccines, hopefully improving the effectiveness of such a biotherapeutic approach.