Ugo Pace

Genetics, diagnosis and management of colorectal cancer (Review)

Colorectal cancer (CRC) is the third most common type of cancer worldwide and a leading cause of cancer death. Surgery represents the mainstay of treatment in early cases but often patients are primarily diagnosed in an advanced stage of disease and sometimes also distant metastases are present. Neoadjuvant therapy is therefore needed but drug resistance may influence response and concur to recurrent disease. At molecular level, it is a very heterogeneous group of diseases with about 30% of hereditary or familial cases. During colorectal adenocarcinomas development, epithelial cells from gastrointestinal trait acquire sequential genetic and epigenetic mutations in specific oncogenes and/or tumour suppressor genes, causing CRC onset, progression and metastasis. Molecular characterization of cancer associated mutations gives valuable information about disease prognosis and response to the therapy. Very early diagnosis and personalized care, as well as a better knowledge of molecular basis of its onset and progression, are therefore crucial to obtain a cure of CRC. In this review, we describe updated genetics, current diagnosis and management of CRC pointing out the extreme need for a multidisciplinary approach to achieve the best results in patient outcomes.

Lithium chloride induces mesenchymal‑to‑epithelial reverting transition in primary colon cancer cell cultures

Epithelial-to-mesenchymal transition (EMT) confers stem cell-like phenotype and more motile properties to carcinoma cells. During EMT, the expression of E-cadherin decreases, resulting in loss of cell-cell adhesion and increased migration. Expression of Twist1 and other pleiotropic transcription factors, such as Snail, is known to activate EMT. We established primary colon cancer cell cultures from samples of operated patients and validated cultures by cytogenetic and molecular biology approaches. Western blot assay, quantitative real-time PCR and immunofluorescence were performed to investigate the expression of E-cadherin, vimentin, β-catenin, cytokeratin-20 and -18, Twist1, Snail, CD44, cyclooxygenase-2 (COX2), Sox2, Oct4 and Nanog. Moreover, cell differentiation was induced by incubation with LiCl-containing medium for 10 days. We observed that these primary colorectal cancer (CRC) cells lost expression of the E-cadherin epithelial marker, which was instead expressed in cancer and normal colon mucosa of the same patient, while overexpressed vimentin (mesenchymal marker), Twist1, Snail (EMT markers) and COX2. Cytokeratin-18 was expressed both in tissues and cell cultures. Expression of stem cell markers, such as CD44, Oct4 and Nanog, were also observed. Following differentiation with the glycogen synthase kinase 3β (GSK3β) inhibitor LiCl, the cells began to express E-cadherin and, at once, Twist1 and Snail expression was strongly downregulated, suggesting a MET-reverting process. In conclusion, we established primary colon mesenchymal cancer cell cultures expressing mesenchymal and epithelial biomarkers together with high level of EMT transcription factors. We propose that they could represent a good model for studying EMT and its reverting mechanism, the mesenchymal-to-epithelial transition (MET). Our observation indicates that LiCl, a GSK3β inhibitor, induces MET in vitro, suggesting that LiCl and GSK3β could represent, respectively, interesting drug, and target for CRC therapy.

The biological complexity of colorectal cancer: Insights into biomarkers for early detection and personalized care

Colorectal cancer has been ranked the third and second most prevalent of all cancers in men and women, respectively, and it represents the fourth most common cause of cancer deaths. In 2012, there were 1.4 million estimated cases of colorectal cancer worldwide, and 700,000 estimated deaths, which implies significant impact on public health, especially in economically-developed countries. In recent years, there has been an increase in the number of tumors, although this has been accompanied by decreased mortality, due to more appropriate and available information, earlier diagnosis, and improvements in treatment. Colorectal cancers are characterized by great genotypic and phenotypic heterogeneity, including tumor microenvironment and interactions between healthy and cancer cells. All of these traits confer a unique peculiarity to each tumor, which can thus be considered as an individual disease. Well conducted molecular and clinical characterization of each colorectal cancer is essential with a view to the implementation of precision oncology, and thus personalized care. This last aims at standardization of therapeutic plans chosen according to the genetic background of each specific neoplasm, to increase overall survival and reduce treatment side effects. Thus, prognostic and predictive molecular biomarkers assume a critical role in the characterization of colorectal cancer and in the determination of the most appropriate therapy.

Evaluation of tumor response after short- course radiotherapy and delayed surgery for rectal cancer

Purpose Neoadjuvant therapy is able to reduce local recurrence in rectal cancer. Immediate surgery after short course radiotherapy allows only for minimal downstaging. We investigated the effect of delayed surgery after short-course radiotherapy at different time intervals before surgery, in patients affected by rectal cancer. Methods From January 2003 to December 2013 sixty-seven patients with the following characteristics have been selected: clinical (c) stage T3N0 ≤ 12 cm from the anal verge and with circumferential resection margin > 5 mm (by magnetic resonance imaging); cT2, any N, < 5 cm from anal verge; and patients facing tumors with enlarged nodes and/or CRM+ve who resulted unfit for chemo-radiation, were also included. Patients underwent preoperative short-course radiotherapy with different interval to surgery were divided in three groups: A (within 6 weeks), B (between 6 and 8 weeks) and C (after more than 8 weeks). Hystopatolgical response to radiotherapy was measured by Mandard’s modified tumor regression grade (TRG). Results All patients completed the scheduled treatment. Sixty-six patients underwent surgery. Fifty-three of which (80.3%) received a sphincter saving procedure. Downstaging occurred in 41 cases (62.1%). The analysis of subgroups showed an increasing prevalence of TRG 1–2 prolonging the interval to surgery (group A—16.7%, group B—36.8% and 54.3% in group C; p value 0.023). Conclusions Preoperative short-course radiotherapy is able to downstage rectal cancer if surgery is delayed. A higher rate of TRG 1–2 can be obtained if interval to surgery is prolonged to more than 8 weeks.

Intracorporeal versus extracorporeal anastomosis after laparoscopic left colectomy for splenic flexure cancer: results from a multi-institutional audit on 181 consecutive patients

Although intracorporeal anastomosis has been demonstrated to be safe and effective after right colectomy, limited data are available about its efficacy after left colectomy for colon cancer located in splenic flexure. A multi-institutional audit was designed, including 92 patients who underwent laparoscopic left colectomy with intracorporeal anastomosis (IA) compared with 89 matched patients who underwent a laparoscopic left colectomy with extracorporeal anastomosis (EA). There was no significant difference in terms of age, sex, BMI, and ASA score between the two groups. Post-surgical history and stage of disease according to AJCC/UICC TNM were also similar. IA and EA groups demonstrated similar oncologic radicality in terms of the number of lymph nodes harvested (18.5 ± 9 vs. 17.5 ± 8.4; p = 0.48). Recovery after surgery was also better in patients who underwent IA, as confirmed by the shorter time to flatus in the IA group (2.6 ± 1.1 days vs. 3.4 ± 1.2 days; p < 0.001) and higher post-operative pain expressed in the mean VAS Scale in the EA group (1.7 ± 2.1 vs. 3.5 ± 1.6; p < 0.001). Laparoscopic left colectomy with intracorporeal anastomosis was associated with a lower rate of post-operative complications (OR 6.7, 95% CI 2.2–20; p = 0.001). However, when stratifying according to Clavien classification, the difference was consistently confirmed for less severe (class I and II) complications (OR 7.6, 95% CI 2.5–23, p = 0.001) but not for class III, IV, and V complications (OR 1.8, 95% CI 0.1–16.9; p = 0.59). Our results were consistent to hypothesize that a complete laparoscopic approach could be considered a safe method to perform laparoscopic left colectomy with the advantage of a guaranteed faster recovery after surgery. Further randomized clinical trials are needed to obtain a more definitive conclusion.

Characterisation of mesenchymal colon tumour-derived cells in tumourspheres as a model for colorectal cancer progression

Cellular plasticity, the ability of cells to switch from an epitheial phenotype to a mesenchymal one and vice versa, plays a crucial role in tumour progression and metastases development. In 20-25% of patients with colon cancer and in 18% of patients with rectal cancer, metastases are present at the time of the first diagnosis. They are the first cause of colorectal cancer (CRC)-related mortality, defining stage IV CRC, which is characterized by a relatively short overall survival. We previously isolated two primary colon adenocarcinoma cell cultures that had undergone epithelial-mesenchymal transition (EMT), one with a high microsatellite instability phenotype (T88) and one with a chromosomal instability phenotype (T93). The aim of this study was to establish a model with which to study EMT, stemness features and cell plasticity in cancer progression and to examine the effects of incubation with lithium chloride (LiCl), a specific glycogen synthase kinase 3 β (GSK-3β) inhibitor, on these cellular processes. Indeed, GSK3β is an important regulator of cell survival, which promotes tumourigenesis in colon cells by facilitating the crosstalk between colorectal cancer pathways. Thus, we further characterized our system of adherent primary mesenchymal colon cancer cells and their paired tumourspheres by examining the expression and localisation of a panel of markers, including E- and N-cadherin, CD133, CD44v6, aldehyde dehydrogenase 1 (ALDH1) and leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5). We also characterised the molecular features of these tumourspheres and examined their response to LiCl. Furthermore, we explored the effects of LiCl on cell motility and plasticity. We demonstrated that LiCl reduced cell migration, stemness features and cell plasticity. We also observed the atypical nuclear localisation of membrane proteins, including N-cadherin, CD133 and CD44v6 in mesenchymal tumour cells. Of note, CD133 and CD44v6 appeared to localise at the plasma membrane in cells with a more epithelial phenotype, suggesting that the cytoplasmic/nuclear localisation of these proteins could favour and characterize cell plasticity in colorectal cancer progression.

Morphological and functional features prognostic factor of magnetic resonance imaging in locally advanced rectal cancer

Background Although imaging can be suggestive of the diagnosis of rectal cancer, the primary imaging role is to assist in treatment triage of histologically diagnosed tumors. The possibility of a multimodal approach in the response to the treatment opens the way for the selection of criteria more personalized to the patient. Purpose To assess the prognostic factor of morphological and functional magnetic resonance imaging (MRI) in rectal cancer. Material and Methods Seventy-seven patients were enrolled and underwent MRI before treatment and 59 patients underwent MRI after treatment. Radiologists evaluated the presence of lesions using a 4-point confidence scale; they recorded anatomical side, extent, and distance from the anorectal junction and distance from the circumferential margin. Tumor location was classified according to the involvement of proximal rectal channel and/or distal rectal channel. Radiologists scored signal intensity on T2-weighted (T2W) images, diffusion-weighted images (DWI), and MRI dynamic enhancement pattern. Tumor regression grade (TRG) and pathological T (pT) were the gold standard. Results Lesion vascularization score before treatment showed a predictive value of complete pathological response (sensitivity 88%, specificity 50%) based on pT, while using TRG lymph node number before treatment (sensitivity 83%, specificity 57%) showed a predictive value for response treatment. T2W signal (sensitivity 78%, specificity 30%) and DWI signal after treatment (sensitivity 78%, specificity 61%) showed a good predictive value for local rectal recurrences. Conclusions Lesion vascularization and lymph node number had a predictive value for neoadjuvant treatment complete response in rectal cancer. T2W signal intensity and DWI signal showed a good predictive value for local rectal recurrences.

Diffusion and perfusion MR parameters to assess preoperative short-course radiotherapy response in locally advanced rectal cancer: a comparative explorative study among Standardized Index of Shape by DCE-MRI, intravoxel incoherent motion- and diffusion kurtosis imaging-derived parameters

PurposeTo assess preoperative short-course radiotherapy (SCR) tumor response in locally advanced rectal cancer (LARC) by means of Standardized Index of Shape (SIS) by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), apparent diffusion coefficient (ADC), intravoxel incoherent motion (IVIM) and diffusion kurtosis imaging (DKI) parameters derived from diffusion-weighted MRI (DW-MRI).Materials and methodsThirty-four patients with LARC who underwent MRI scans before and after SCR followed by delayed surgery, retrospectively, were enrolled. SIS, ADC, IVIM parameters [tissue diffusion (Dt), pseudo-diffusion (Dp), perfusion fraction (fp)] and DKI parameters [mean diffusivity (MD), mean of diffusional kurtosis (MK)] were calculated for each patient. IVIM parameters were estimated using two methods, namely conventional biexponential fitting (CBFM) and variable projection (VARPRO). After surgery, the pathological TNM and tumor regression grade (TRG) were estimated. For each parameter, percentage changes between before and after SCR were evaluated. Furthermore, an artificial neural network was trained for outcome prediction. Nonparametric sample tests and receiver operating characteristic curve (ROC) analysis were performed.ResultsFifteen patients were classified as responders (TRG ≤ 2) and 19 as not responders (TRG > 3). Seven patients had TRG 1 (pathological complete response, pCR). Mean and standard deviation values of pre-treatment CBFM Dp and mean value of VARPRO Dp pre-treatment showed statistically significant differences to predict pCR. (p value at Mann–Whitney test was 0.05, 0.03 and 0.008, respectively.) Exclusively SIS percentage change showed significant differences between responder and non-responder patients after SCR (p value << 0.001) and to assess pCR after SCR (p value << 0.001). The best results to predict pCR were obtained by VARPRO Fp mean value pre-treatment with area under ROC of 0.84, a sensitivity of 96.4%, a specificity of 71.4%, a positive predictive value (PPV) of 92.9%, a negative predictive value (NPV) of 83.3% and an accuracy of 91.2%. The best results to assess after treatment complete pathological response were obtained by SIS with an area under ROC of 0.89, a sensitivity of 85.7%, a specificity of 92.6%, a PPV of 75.0%, a NPV of 96.1% and an accuracy of 91.2%. Moreover, the best results to differentiate after treatment responders vs. non-responders were obtained by SIS with an area under ROC of 0.94, a sensitivity of 93.3%, a specificity of 84.2%, a PPV of 82.4%, a NPV of 94.1% and an accuracy of 88.2%. Promising initial results were obtained using a decision tree tested with all ADC, IVIM and DKI extracted parameter: we reached high accuracy to assess pathological complete response after SCR in LARC (an accuracy of 85.3% to assess pathological complete response after SCR using VARPRO Dp mean value post-treatment, ADC standard deviation value pre-treatment, MD standard deviation value post-treatment).ConclusionSIS is a hopeful DCE-MRI angiogenic biomarker to assess preoperative treatment response after SCR with delayed surgery. Furthermore, an important prognostic role was obtained by VARPRO Fp mean value pre-treatment and by a decision tree composed by diffusion parameters derived by DWI and DKI to assess pathological complete response.

Feasibility and advantages of transanal minimally invasive surgery: a 7-year experience with 76 cases

Background: Transanal minimally invasive surgery (TAMIS) is appropriate for benign lesions that are not suitable to flexible endoscopic excision, and it can be a valuable option for malignant rectal disease, in carefully selected patients. The authors report their 7-year experience with TAMIS for treatment of rectal tumours. Methods: From May 2010 to May 2017, 76 patients un-derwent local excision of rectal lesions by a TAMIS approach. Results: Between May 2010 and May 2017, 76 patients were treated with the TAMIS approach. Of these 58% were male and 42% were female. The average age was 68 years and the average distance from the anal verge was 6 cm. The postoperative pathology reported low grade rectal adenoma (22%), high grade rectal ade-noma (20%), rectal adenocarcinoma (54%) and benign rectal lesion (4%). Twenty-two patients have had a neoadjuvant chemoradiotherapy. At mean follow-up of 48 months (range, 1–83 months) no fecal incontinence or other anorectal dysfunction. Local recurrence was observed in 3 patients (2 malignant, 1 benign). Conclusions: In this study, TAMIS confirmed to be a safety and feasible treatment option for precancerous polyps and early-stage rectal cancers with favorable histology.