Biomarkers in colorectal cancer: Current clinical utility and future perspectives

Colorectal cancer(CRC) is a major cause of cancer death worldwide. CRC has poor prognosis and there is a crucial need for new diagnostic and prognostic biomarkers to avoid CRC-related deaths. CRC can be considered a sporadic disease in most cases(75%-80%), but it has been suggested that crosstalk between gene mutations(i.e., mutations of BRAF, KRAS, and p53 as well as microsatellite instability) and epigenetic alterations(i.e., DNA methylation of Cp G island promoter regions) could play a pivotal role in cancer development. A number of studies have focused on molecular testing to guide targeted and conventional treatments for patients with CRC, sometimes with contrasting results. Some of the most useful innovations in the management of CRC include the possibility to detect the absence of KRAS, BRAF, NRAS and PIK3 CA gene mutations with the subsequent choice to administer targeted adjuvant therapy with anti-epidermal growth factor receptor antibodies. Moreover, CRC patients can benefit from tests for microsatellite instability and for the detection of loss of heterozygosity of chromosome 18 q that can be helpful in guiding therapeutic decisions as regards the administration of 5-FU. The aim of this review was to summarize the most recent evidence on the possible use of genetic or epigenetic biomarkers for diagnosis, prognosis and response to therapy in CRC patients.

Markers of bile duct tumors

Biliary tract carcinomas are relatively rare,representing less than 1%of cancers.However,their incidence has increased in Japan and in industrialized countries like the USA.Biliary tract tumors have a poor prognosis and a high mortality rate because they are usually detected late in the course of the disease;therapeutic treatment options are often limited and of minimal utility.Recent studies have shown the importance of serum and molecularmarkers in the diagnosis and follow up of biliary tract tumors.This review aims to introduce the main features of the most important serum and molecular markers of biliary tree tumors.Some considerable tumor markers are cancer antigen 125,carbohydrate antigen 19-9,carcinoembryonic antigen,chromogranin A,mucin 1,mucin 5,alpha-fetoprotein,claudins and cytokeratins.

Familial adenomatous polyposis and changes in the gut microbiota: New insights into colorectal cancer carcinogenesis

Patients with familial adenomatous polyposis(FAP),an autosomal dominant hereditary colorectal cancer syndrome,have a lifetime risk of developing cancer of nearly 100%.Recent studies have pointed out that the gut microbiota could play a crucial role in the development of colorectal adenomas and the consequent progression to colorectal cancer.Some gut bacteria,such as Fusobacterium nucleatum,Escherichia coli,Clostridium difficile,Peptostreptococcus,and enterotoxigenic Bacteroides fragilis,could be implicated in colorectal carcinogenesis through different mechanisms,including the maintenance of a chronic inflammatory state,production of bioactive tumorigenic metabolites,and DNA damage.Studies using the adenomatous polyposis coliMin/+mouse model,which resembles FAP in most respects,have shown that specific changes in the intestinal microbial community could influence a multistep progression,the intestinal“adenoma-carcinoma sequence”,which involves mucosal barrier injury,low-grade inflammation,activation of the Wnt pathway.Therefore,modulation of gut microbiota might represent a novel therapeutic target for patients with FAP.Administration of probiotics,prebiotics,antibiotics,and nonsteroidal anti-inflammatory drugs could potentially prevent the progression of the adenoma-carcinoma sequence in FAP.The aim of this review was to summarize the best available knowledge on the role of gut microbiota in colorectal carcinogenesis in patients with FAP.

Markers of systemic inflammation and colorectal adenoma risk: Meta-analysis of observational studies

To perform a meta-analysis of observational studies on inflammatory markers levels and occurrence of colorectal adenoma.METHODSPubMed and EMBASE databases were searched until March 2016 for the articles reporting on the circulating levels of inflammatory markers, including: C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) and risk of colorectal adenoma. Random-effects models were used to calculate summary odds ratios (ORs) with 95%CIs for the highest vs lowest category of exposure. Heterogeneity was assessed by using the Q test and I2 statistic. Subgroup analyses were also performed to test for potential source of heterogeneity.RESULTSA total of 14 case-control studies were included. Ten studies on CRP including a total of 3350 cases and 4168 controls showed non-significant summary (OR = 1.23, 95%CI: 0.98-1.54; I2 = 54%, Pheterogeneity = 0.01) in the general analysis, but significant increased odds when considering only advanced adenoma (OR = 1.59, 95%CI: 1.09-2.32; I2 = 44%, Pheterogeneity = 0.15). Subgroup and stratified analyses revealed a potential influence of smoking status and aspirin use on the association between CRP levels and colorectal adenoma. Five studies examined the association between circulating levels of TNF-α and colorectal adenoma risk, including a total of 1,568 cases and 2,832 controls. The summary OR for the highest vs the lowest category of exposure was 1.00 (95%CI: 0.77-1.29). The relationship between circulating IL-6 levels and colorectal adenoma risk was investigated in 7 studies including a total of 1936 cases and 3611 controls. The summary OR for the highest vs the lowest category of exposure was 1.19 (95%CI: 0.92-1.55).CONCLUSIONSummary of current evidence suggests a positive association of CRP levels and advanced colorectal adenoma risk. The role of potential confounding factors should be further evaluated.

Role of surgery for colorectal cancer in the elderly

The prevalence of subjects with colorectal cancer is expected to grow in the next future decades and surgery represents the most successful treatment modality for these patients. Anyway, currently elderly subjects undergo less elective surgical procedures than younger patients mainly due to the high rates of postoperative morbidity and mortality. Some authors suggest extensive surgery, including multistage procedures, as carried out in younger patients while others promote less aggressive surgery. In older patients, laparoscopic-assisted colectomy showed a number of advantages compared to conventional open surgery that include lower stress, higher rate of independency after surgery, quicker return to prior activities and a decrease in costs. The recent advances in chemotherapy and the introduction of new surgical procedures such as the endoluminal stenting, suggest the need for a revisitation of surgical practice patterns and the role of palliative surgery, mainly for patients with advanced disease. In this article, we discuss the current role of surgery for elderly patients with colorectal cancer.

Natural heme oxygenase-1 inducers in hepatobiliary function

Many physiological effects of natural antioxidants, their extracts or their major active components, have been reported in recent decades. Most of these compounds are characterized by a phenolic structure, similar to that of o-tocopherol, and present antioxidant properties that have been demonstrated both in vitro and in vivo. Polyphenors may increase the capacity of endogenous antioxidant defences and modulate the cellular redox state. Changes in the cellular redox state may have wide-ranging consequences for cellular growth and differentiation. The majority of in vitro and in vivo studies conducted so far have attributed the protective effect of bioactive polyphenols to their chemical reactivity toward free radicals and their capacity to prevent the oxidation of important intracellular components. However, in recent years a possible novel aspect inthe mode of action of these compounds has been suggested; that is, the ultimate stimulation of the heme oxygenase-1 （HO-1） pathway is likely to account for the established and powerful antioxidant/anti-inflammatory properties of these polyphenols. The products of the HO-catalyzed reaction, particularly carbon mon- oxide （CO） and biliverdin/bilirubin have been shown to exert protective effects in several organs against oxidative and other noxious stimuli. In this context, it is interesting to note that induction of HO-1 expression by means of natural compounds contributes to protection against liver damage in various experimental models. The focus of this review is on the significance of targeted induction of HO-1 as a potential therapeutic strategy to protect the liver against various stressors in several pathological conditions.

Laparoscopic step 1 ALPPS with microwave transection of theliver for Klatskin tumors:Is it worthwhile?

To the Editor：Associating liver partition and portal vein ligation for stagedhepatectomy （ALPPS） was introduced in 2007 [1]. This techniqueis now used worldwide and has a wide spectrum of indications.However, scientific debate and un-regulated surgical experimentationconcerning the application of this technique led the surgeons to organize the first Consensus Meeting [2] to build a scientificconsensus. One of the most controversial indications to ALPPS isits application for Klatskin tumors. The aim of this letter is to analyzethe critical aspects of laparoscopic microwave ALPPS for radicalsurgical treatment of Klatskin tumors.

Is the Bismuth-Corlette IIIb stage really an unfavorable situation for resectability of Klatskin tumors?A critical appraisal

We read with considerable interest the paper from Passeri et al.[1]questioning how the IIIb preoperative determination of a Klatskin tumor could be considered a risk factor for unresectability,and we could not refrain from making some critical recommendations about it.Although the paper was nicely written,in our opinion,no meaningful conclusion should however be drawn from it,due to the small sample size of the reported series.