Colorectal cancer tumour markers and biomarkers:Recenttherapeutic advances

Colorectal cancer(CRC) is the second most commonly diagnosed cancer among females and third among males worldwide. It also contributes significantly to cancer-related deaths, despite the continuous progress in diagnostic and therapeutic methods. Biomarkers currently play an important role in the detection and treatment of patients with colorectal cancer. Risk stratification for screening might be augmented by finding new biomarkers which alone or as a complement of existing tests might recognize either the predisposition or early stage of the disease. Biomarkers have also the potential to change diagnostic and treatment algorithms by selecting the proper chemotherapeutic drugs across a broad spectrum of patients. There are attempts to personalise chemotherapy based on presence or absence of specific biomarkers. In this review, we update review published last year and describe our understanding of tumour markers and biomarkers role in CRC screening, diagnosis, treatment and follow-up. Goal of future research is to identify those biomarkers that could allow a non-invasive and cost-effective diagnosis, as well as to recognise the best prognostic panel and define the predictive biomarkers for available treatments.

Non-polypoid colorectal neoplasms:Classification,therapy and follow-up

In the last years,an increasing interest has been raised on non-polypoid colorectal tumors(NPT) and in particular on large flat neoplastic lesions beyond 10 mm tending to grow laterally,called laterally spreading tumors(LST).LSTs and large sessile polyps have a greater frequency of high-grade dysplasia and local invasiveness as compared to pedunculated lesions of the same size and usually represent a technical challenge for the endoscopist in terms of either diagnosis and resection.According to the Paris classification,NPTs are distinguished in slightly elevated(0-Ⅱa,less than 2.5 mm),flat(0-Ⅱb) or slightly depressed(0-Ⅱc).NPTs are usually flat or slightly elevated and tend to spread laterally while in case of depressed lesions,cell proliferation growth progresses in depth in the colonic wall,thus leading to an increased risk of submucosal invasion(SMI) even for smaller neoplasms.NPTs may be frequently missed by inexperienced endoscopists,thus a careful training and precise assessment of all suspected mucosal areas should be performed.Chromoendoscopy or,if possible,narrow-band imaging technique should be considered for the estimation of SMI risk of NPTs,and the characterization of pit pattern and vascular pattern may be useful to predict the risk of SMI and,therefore,to guide the therapeutic decision.Lesions suitable to endoscopic resection are those confined to the mucosa(or superficial layer of submucosa in selected cases) whereas deeper invasion makes endoscopic therapy infeasible.Endoscopic mucosal resection(EMR,piecemeal for LSTs > 20 mm,en bloc for smaller neoplasms) remains the first-line therapy for NPTs,whereas endoscopic submucosal dissection in high-volume centers or surgery should be considered for large LSTs for which en bloc resection is mandatory and cannot be achieved by means of EMR.After piecemeal EMR,follow-up colonoscopy should be performed at 3 mo to assess resection completeness.In case of en bloc resection,surveillance colonoscopy should be scheduled at 3 years for adenomatous lesions ≥ 1 cm,or in presence of villous features or high-grade dysplasia patients(regardless of the size),while less intensive surveillance(colonoscopy at 5-10 years) is needed in case of single(or two) NPT < 1 cm presenting tubular features or low-grade dysplasia at histology.

Crosstalk between tumor cells and microenvironment via Wnt pathway in colorectal cancer dissemination

Invasion and metastasis are the deadly face of malignant tumors. Considering the high rate of incidence and mortality of colorectal cancer, it is critical to determine the mechanisms of its dissemination. In the parallel investigation of the invasive front and tumor center area of colorectal cancer (CRC), observation of heterogeneous β-catenin distribution and epithelial-mesenchymal transition (EMT) at the invasive front suggested that there might be a crosstalk between tumor cells and the tumor microenvironment. Wnt signaling pathway is also involved in the cancer progression due to its key role in CRC tumorigenesis. Moreover, in recent years, there is increasing evidence that the regulators of microenvironment, including extracellular matrix, growth factors and inflammatory factors, are associated with the activation of Wnt pathway and the mobility of tumor cells. In this review, we will try to explain how these molecules trigger metastasis via the Wnt pathway.

Role of probiotics,prebiotics and synbiotics in chemoprevention for colorectal cancer

Colorectal cancer is the third most common form of cancer.Current treatments are all associated with a high risk of complications and a low success rate.Recently,synbiotics have been proposed as a new preventive and therapeutic option.There is no direct experimental evidence for cancer suppression in humans as a result of the consumption of pro-,pre-or synbiotics.However,there is a wealth of evidence emerging from laboratory studies.The mechanisms by which pro-,pre-and synbiotics may inhibit colon cancer are now beginning to be understood and will be addressed in the present review.

Hypoalbuminemia in colorectal cancer prognosis:Nutritional marker or inflammatory surrogate?

Albumin is the single most abundant protein in the human serum. Its roles in physiology and pathology are diverse. Serum albumin levels have been classically thought to reflect the nutritional status of patients. This concept has been challenged in the last two decades as multiple factors, such as inflammation, appeared to affect albumin levels independent of nutrition. In general, cancer patients have a high prevalence of hypoalbuminemia. As such, the role of hypoalbuminemia in patients with colorectal cancer has received significant interest. We reviewed the English literature on the prognostic value of pretreatment albumin levels in colorectal cancer. We also consolidated the evidence that led to the current understanding of hypoalbuminemia as an inflammatory marker rather than as a nutritional one among patients with colorectal cancer.

Capecitabine and irinotecan with and without bevacizumab for advanced colorectal cancer patients

AIM:To investigate the efficacy and safety of capecitabine plus irinotecan±bevacizumab in advanced or metastatic colorectal cancer patients. METHODS:Forty six patients with previously untreated,locally-advanced or metastatic colorectal cancer(mCRC) were recruited between 2001-2006 in a prospective open-label phaseⅡtrial,in German community-based outpatient clinics.Patients received a standard capecitabine plus irinotecan(CAPIRI) or CAPIRI plus bevacizumab(CAPIRI-BEV) regimen every 3 wk. Dose reductions were mandatory from the first cycle in cases of>grade 2 toxicity.The treatment choice of bevacizumab was at the discretion of the physician.Theprimary endpoints were response and toxicity and secondary endpoints included progression-free survival and overall survival. RESULTS:In the CAPIRI group vs the CAPRI-Bev group there were more female than male patients(47% vs 24%) ,and more patients had colon as the primary tumor site(58.8%vs 48.2%) with fewer patients having sigmoid colon as primary tumor site(5.9%vs 20.7%) .Grade 3/4 toxicity was higher with CAPIRI than CAPIRI-Bev:82%vs 58.6%.Partial response rates were 29.4%and 34.5%,and tumor control rates were 70.6%and 75.9%,respectively.No complete responses were observed.The median progression-free survival was 11.4 mo and 12.8 mo for CAPIRI and CAPIRI-Bev,respectively.The median overall survival for CAPIRI was 15 mo(458 d) and for CAPIRI-Bev 24 mo(733 d) .These differences were not statistically different.In the CAPIRI-Bev,group,two patients underwent a full secondary tumor resection after treatment,whereas in the CAPIRI group no cases underwent this procedure. CONCLUSION:Both regimens were well tolerated and offered effective tumor growth control in this outpatient setting.Severe gastrointestinal toxicities and thromboembolic events were rare and if observed were never fatal.

Diagnosis and treatment of Gardner syndrome with gastric polyposis: A case report and review of the literature

Gardner syndrome (GS) is an autosomal dominant disease characterized by the presence of colonic polyposis, osteoma and soft tissue tumors. It is regarded as a clinical subgroup of familial adenomatous polyposis (FAP) and may present at any age from 2 mo to 70 years with a variety of symptoms, either colonic or extracolonic. We present a case of a 23-year-old female patient with GS who presented with gastric polyposis and was successively treated with restorative proctocolectomy in combination with ileal pouch anal anastomosis (RPC/ IPAA), ileostomy, ileostomy closure operation, snare polypectomy during 8 mo. After operation, the patient took oral traditional Chinese medicine pills made of Fructus mume and Bombyx batryticatu for about 6 mo. The innutrition and anaemia of this patient were gradually improved. Gastroscopy showed that the remnant gastric polypi gradually decreased and finally disappeared 19 mo after the first operation. The patient had 2-3 times of solid stool per day at the time we wrote this paper.

CREB-binding protein, p300, butyrate, and Wnt signaling in colorectal cancer

This paper reviews the distinctive roles played by the transcriptional coactivators CREB-binding protein(CBP) and p300 in Wnt/β-catenin signaling and cell physiology in colorectal cancer(CRC). Specifically, we focus on the effects of CBP- and p300-mediated Wnt activity on(1) neoplastic progression;(2) the activities of butyrate, a breakdown product of dietary fiber, on cell signaling and colonic cell physiology;(3) the development of resistance to histone deacetylase inhibitors(HDACis), including butyrate and synthetic HDACis, in colonic cells; and(4) the physiology and number of cancer stem cells. Mutations of the Wnt/β-catenin signaling pathway initiate the majority of CRC cases, and we have shown that hyperactivation of this pathway by butyrate and other HDACis promotes CRC cell apoptosis. This activity by butyrate may in part explain the preventive action of fiber against CRC. However, individuals with a high-fiber diet may still develop neoplasia; therefore, resistance to the chemopreventive action of butyrate likely contributes to CRC. CBP or p300 may modify the ability of butyrate to influence colonic cell physiology since the two transcriptional coactivators affect Wnt signaling, and likely, its hyperactivation by butyrate. Also, CBP and p300 likely affect colonic tumorigenesis, as well as stem cell pluripotency. Improvement of CRC prevention and therapy requires a better understanding of the alterations in Wnt signaling and gene expression that underlie neoplastic progression, stem cell fate, and the development of resistance to butyrate and clinically relevant HDACis. Detailed knowledge of how CBP- and p300 modulate colonic cell physiology may lead to new approaches for anti-CRC prevention and therapeutics, particularly with respect to combinatorial therapy of CBP/p300 inhibitors with HDACis.

Evaluation of serum catnepsin B and D in relation to diniGopatnological staging of colorectal cancer

AIM: Proteolytic degradation of the extracellular matrix facilitates cancer invasion and promotes metastasis. The study aims at evaluation of preoperative and postoperative serum cathepsins B and D levels in correlation with selected anatomoclinical features of colorectal cancer.METHODS: Blood samples were collected from 63colorectal cancer patients before curative operation of the tumor 10 d later. Blood that was obtained from 20healthy volunteers, served as a control. The activity of cathepsin B was measured with Bz-DL-arginine-pNA as a substrate at pH 6.0, while cathepsin D activity was determined with urea-denatured hemoglobin (pH 4.0).RESULTS: The preoperative and postoperative activities of cathepsin B were significantly (P＜0.00001) lower in serum of colorectal cancer patients than in control group.However, postoperative values of this protease were significantly increased in comparison with preoperative ones (P = 0.031). Activity of cathepsin D appeared to be significantly higher in colorectal cancer sera (P＜0.00001)compared with controls. No statistically significant differences between preoperative and postoperative activity of cathepsin D were noted (P = 0.09). We revealed a strong linkage of cathepsins' levels with lymph node status and pT stage of colorectal cancer.CONCLUSION: Blood serum activities of cathepsin B and D depend on the time of sampling, tumor size and lymph node involvement. Significantly, increased activity of cathepsin D could indicate a malignant condition of the large intestine. In our work, the serum postoperative decrease of cathepsin B activity appears as an obvious concomitant of local lymph node metastasis-the wellknown clinicopathological feature of poor prognosis.

Hypoxia-inducible factor-1 modulates upregulation of mutT homolog-1 in colorectal cancer

AIM: To investigate the roles and interactions of mut T homolog(MTH)-1 and hypoxia-inducible factor(HIF)-1α in human colorectal cancer(CRC).METHODS: The expression and distribution of HIF-1α and MTH-1 proteins were detected in human CRC tissues by immunohistochemistry and quantitative realtime polymerase chain reaction(q RT-PCR). SW480 and HT-29 cells were exposed to normoxia or hypoxia. Protein and m RNA levels of HIF-1α and MTH-1 were analyzed by western blotting and q RT-PCR, respectively. In order to determine the effect of HIF-1α on the expression of MTH-1 and the amount of 8-oxodeoxyguanosine triphosphate(d GTP) in SW480 and HT-29 cells, HIF-1α was silenced with small interfering RNA(si RNA). Growth studies were conducted on cells with HIF-1α inhibition using a xenograft tumor model. Finally, MTH-1 protein was detected by western blotting in vivo.RESULTS: High MTH-1 m RNA expression was detected in 64.2% of cases(54/84), and this was significantly correlated with tumor stage(P = 0.023) and size(P = 0.043). HIF-1α protein expression was correlated significantly with MTH-1 expression(R = 0.640; P < 0.01) in human CRC tissues. Hypoxic stress induced m RNA and protein expression of MTH-1 in SW480 and HT-29 cells. Inhibition of HIF-1α by si RNA decreased the expression of MTH-1 and led to the accumulation of 8-oxo-d GTP in SW480 and HT-29 cells. In the in vivo xenograft tumor model, expression of MTH-1 was decreased in the HIF-1α si RNA group, and the tumor volume was much smaller than that in the mock si RNA group.CONCLUSION: MTH-1 expression in CRC cells was upregulated via HIF-1α in response to hypoxic stress, emphasizing the crucial role of HIF-1α-induced MTH-1 in tumor growth.

Long-term outcomes after stenting as a"bridge to surgery"for the management of acute obstruction secondary tocolorectal cancer

Obstructive symptoms are present in 8% of cases at the time of initial diagnosis in cases of colorectal cancer. Emergency surgery has been classically considered the treatment of choice in these patients. However, in the majority of studies, emergency colorectal surgery is burdened with higher morbidity and mortality rates than elective surgery, and many patients require temporal colostomy which deteriorates their quality of life and becomes permanent in 10%-40% of cases. The aim of stenting by-pass to surgery is to transform emergency surgery into elective surgery in order to improve surgical results, obtain an accurate tumoral staging and detection of synchronous lesions, stabilization of comorbidities and performance of laparoscopic surgery. Immediate results were more favourable in patients who were stented concerning primary anastomosis, permanent stoma, wound infection and overall morbidity, having the higher surgical risk patients the greater benefit. However, some findings laid out the possible implication of stenting in long-term results of oncologic treatment. Perforation after stenting is related to tumoral recurrence. In studies with perforation rates above 8%, higher recurrences rates in young patients and lower disease free survival have been shown. On the other hand, after stenting the number of removed lymph nodes in the surgical specimen is larger, patients can receive adjuvant chemotherapy earlier and in a greater percentage and the number of patients who can be surgically treated with laparoscopic surgery is larger. Finally, there are no consistent studies able to demonstrate that one strategy is superior to the other in terms of oncologic benefits. At present, it would seem wise to assume a higher initial complication rate in young patients without relevant comorbidities and to accept the risk of local recurrence in old patients(> 70 years) or with high surgical risk(ASA Ⅲ/Ⅳ).

Effect of ageing on colonic mucosal regeneration

The physiologic and pathologic cellular and molecular changes occurring with age in the human colon affect both the inflammatory process leading to mucosal injury and the regenerative capacity of the epithelium.On the one hand,age-related telomere shortening and inflamm-ageing may lead to the development of colonic inflammation,which results in epithelial damage.On the other hand,the altered migration and function of regenerative stem cells,the age-related methylation of mucosal healing-associated genes,together with the alterations of growth factor signaling with age,may be involved in delayed mucosal regeneration.The connections of these alterations to the process of ageing are not fully known.The understanding and customtailored modification of these mechanisms are of great clinical importance with regard to disease prevention and modern therapeutic strategies.Here,we aim to summarize the age-related microscopic and molecular changes of the human colon,as well as their role in altered mucosal healing.

Role of a liver-first approach for synchronous colorectalliver metastases

AIM: To evaluate the feasibility and survival outcomes of a liver-first approach.METHODS: Between January 2009 and April 2013, 18 synchronous colorectal liver metastases(s CRLMs) patients with a planned liver-first approach in the Hepatopancreatobiliary Surgery Department Ⅰ of the Beijing Cancer Hospital were enrolled in this study. Clinical data, surgical outcomes, morbidity and mortality rates were collected. The feasibility and long-term outcomes of the approach were retrospectively analyzed.RESULTS: Sixteen patients(88.9%) completed the treatment protocol for primary and liver tumors. The main reason for treatment failure was liver disease recurrence. The 1 and 3 year overall survival rates were 94.4% and 44.8%, respectively. The median survival time was 30 mo. The postoperative morbidity and mortality were 22.2% and 0%, respectively, following a hepatic resection, and were 18.8% and 0%, respectively, after a colorectal surgery.CONCLUSION: The liver-first approach appeared to be feasible and safe. It can be performed with a comparable mortality and morbidity to the traditional treatment paradigm. This approach might offer a curative opportunity for s CRLM patients with a high liver disease burden.

Cardiac metastasis from colorectal cancer:A case report

The heart is an unusual site of metastasis from any malignancy. We report a case of cardiac metastasis from colorectal cancer. A 70-year-old woman was referred with a presumptive diagnosis of sigmoid colon cancer with cardiac myxoma. Two-dimensional echocardiography showed a 4 cm x 4.5 cm mobile mass on the lateral right atrial wall, and computed tomography revealed a low attenuated Iobulating mass in the right atrium. The patient underwent anterior resection for sigmoid colon cancer （T4N2）. Thereafter, she experienced progressive shortness of breath. Therefore, a cardiac operation was performed 2 wk after the colorectal operation. Histological examination revealed adenocarcinoma, which was identical to the primary lesion. Although two- dimensional echocardiography has become the diagnostic test of choice for detecting cardiac tumors, in patients with colorectal cancer showing a cardiac mass, further diagnostic evaluation such as a magnetic resonance imaging might be necessary.

Anti-angiogenic agents in metastatic colorectal cancer

Colorectal cancer(CRC) is a major public health concern being the third leading cause of cancer mortality in the United States. The availability of better therapeutic options has led to a decline in cancer mortality in these patients. Surgical resection should be considered in all stages of the disease. The use of conversion therapy has made surgery a potentially curative option even in patients with initially unresectable metastatic disease. In this review we discuss the role of various antiangiogenic agents in patients with metastatic CRC(m CRC). We describe the mechanism of action of these agents, and the rationale for their use in combination with chemotherapy. We also review important clinical studies that have evaluated the safety and efficacy of these agents in m CRC patients. Despite the discovery of several promising anti-angiogenic agents, m CRC remains an incurable disease with a median overall survival of just over 2 years in patients exposed to all available treatment regimens. Further insights into tumor biology and tumor microenvironment may help improve outcomes in these patients.

Novel rapid tissue lysis method to evaluate cancer proteins: Correlation between elevated Bcl-X_L expression and colorectal cancer cell proliferation

AIM： We optimized a rapid and efficient tissue lysis method using the MagNA Lyser （Roche, Germany）. Using this novel method combined with immunoblot analysis, we investigated the correlation between abnormal Bcl-XL expression and clinicopathological characteristics in colorectal cancer. METHODS： Tissue samples from Sprague-Dawley rats were tested to determine optimal lysis conditions for use with MagNA Lyser. We next used the new method to extract tissue proteins from the tumor tissue of a colorectal cancer patient. The availability of extractable tissue proteins for proteomic study was demonstrated by two-dimensional （2D） gel electrophoresis and subsequent matrix-assisted laser desorption/ionization time-of-flight （MALDI-TOF） mass spectrometry. In addition, we prepared tissue lysates from paired tumor tissues and adjacent nontumor tissues of 50 colorectal carcinoma patients. Ensuing immunoblot analyses were performed to detect the level of Bcl-X, expression. RESULTS： The optimal sample sizes processed were found to be around 200 mg, with oscillation frequency of 6 500 r/rain for 80 s. Test of the first human tissue lysate confirmed that the MagNA Lyser method was adequate for protein extraction and subsequent identification by current proteomic protocols. The method was also applicable to immunoblot analysis. Thirty of 50 （60%） colorectal patients exhibited higher level of Bcl-XL expression in their tumor tissues. Raised level of Bcl-XL expression correlated with patients＇ gender and tumor cell proliferation index （P= 0.037 and P〈0.001, respectively）, but was independent of clinicopathological characteristics and overall survival. CONCLUSION： We report a novel tissue lysis method applicable to proteomic and immunoblot analyses, which can facilitate the discovery and detection of cancer protein alterations.

Clinical and biological characteristics of colorectal cancer with familial predisposition

Objective:To evaluatethemicrosatelliteinstability(MSI),expressionof mismatchrepair(MMR)gene(hMLH1,hMSH2)andproliferationkineticsincolorectalcancer(CRC)withfamilialpredisposition.Method:Forty-sixcasesof CRC were studiedusingsilverstainingpolymerasechainreaction-singlestrandconformation polymorphism(PCR-SSCP)technique,streptavidin-peroxidase(SP)immunohistochemicalmethodand flowcyto-metry.Results:In CRCpatientswithfamilialpredisposition,theMSI-positiveratewas higherthanin sporadicCRC(P<0.05).FamilialpredispositionandpositiveMSIwerestronglyrelatedto earlyageof canceronset,theproclivity for proximalcoloniccancer,poordifferentiatedandextracolorectalnmalignancies(P<0.01,P<0.05).Theincidence of negativeexpressionof hMLH1intumortissueandhMLH1,hMSH2innormalcolorectaltissueswassignificantly higher(P<0.05).Thenegativeexpressionof hMLH1togetherwithhMSH2was relatedwithpositiveMSI(P<0.05).InMSI-positiveCRCcells,theproliferationcellnucleusantigen(PCNA)expression,proliferationindexandS-phase cellsdecreasedobviously(P<0.01,P<0.05).Conclusion:In CRCwithfamilialpredisposition,MSI mightbe an importantcontributor.Therateof hMLH1andhMSH2mutationincreasedintumorandnormaltissue,andtheproli-ferationactivityof theircancercellwaslower.

MiR-139-5p inhibits migration and invasion of colorectal cancer by downregulating AMFR and NOTCH1

MicroRNAs （miRNAs） that exert function by posttran- scriptional suppression have recently brought insight in our understanding of the role of non.protein-coding RNAs in carcinogenesis and metastasis. In this study, we described the function and molecular mechanism of miR-139-5p in colorectal cancer （CRC） and its potential clinical application in CRC. We found that miR-139-5p was significantly downregulated in 73.8% CRC samples compared with adjacent noncancerous tissues （NCTs）, and decreased miR-139-5p was associated with poor prognosis. Functional analyses demonstrated that ectopic expression of miR-139-5p suppressed CRC cell migration and invasion in vitro and metastasis in vivo. Mechanistic investigations revealed that miR-139-5p suppress CRC cell invasion and metastasis by targeting AMFR and NOTCH1. Knockdown of the two genes phe- nocopied the inhibitory effect of miR-139-5p on CRC metastasis. Furthermore, the protein levels of the two genes were upregulated in CRC samples compared with NCTs, and inversely correlated with the miR-139-5p expression. Increased NOTCH1 protein expression was correlated with poor prognosis of CRC patients. Together, our data indicate that miR-139-5p is a potentialtumor suppressor and prognostic factor for CRC, and targeting miR-139-5p may repress the metastasis of CRC and improve survival.