Andrea Muratore

Stromal contribution to the colorectal cancer transcriptome

Recent studies identified a poor-prognosis stem/serrated/mesenchymal (SSM) transcriptional subtype of colorectal cancer (CRC). We noted that genes upregulated in this subtype are also prominently expressed by stromal cells, suggesting that SSM transcripts could derive from stromal rather than epithelial cancer cells. To test this hypothesis, we analyzed CRC expression data from patient-derived xenografts, where mouse stroma supports human cancer cells. Species-specific expression analysis showed that the mRNA levels of SSM genes were mostly due to stromal expression. Transcriptional signatures built to specifically report the abundance of cancer-associated fibroblasts (CAFs), leukocytes or endothelial cells all had significantly higher expression in human CRC samples of the SSM subtype. High expression of the CAF signature was associated with poor prognosis in untreated CRC, and joint high expression of the stromal signatures predicted resistance to radiotherapy in rectal cancer. These data show that the distinctive transcriptional and clinical features of the SSM subtype can be ascribed to its particularly abundant stromal component.

The genomic landscape of response to EGFR blockade in colorectal cancer

Colorectal cancer is the third most common cancer worldwide, with 1.2 million patients diagnosed annually. In late-stage colorectal cancer, the most commonly used targeted therapies are the monoclonal antibodies cetuximab and panitumumab, which prevent epidermal growth factor receptor (EGFR) activation. Recent studies have identified alterations in KRAS and other genes as likely mechanisms of primary and secondary resistance to anti-EGFR antibody therapy. Despite these efforts, additional mechanisms of resistance to EGFR blockade are thought to be present in colorectal cancer and little is known about determinants of sensitivity to this therapy. To examine the effect of somatic genetic changes in colorectal cancer on response to anti-EGFR antibody therapy, here we perform complete exome sequence and copy number analyses of 129 patient-derived tumour grafts and targeted genomic analyses of 55 patient tumours, all of which were KRAS wild-type. We analysed the response of tumours to anti-EGFR antibody blockade in tumour graft models and in clinical settings and functionally linked therapeutic responses to mutational data. In addition to previously identified genes, we detected mutations in ERBB2, EGFR, FGFR1, PDGFRA, and MAP2K1 as potential mechanisms of primary resistance to this therapy. Novel alterations in the ectodomain of EGFR were identified in patients with acquired resistance to EGFR blockade. Amplifications and sequence changes in the tyrosine kinase receptor adaptor gene IRS2 were identified in tumours with increased sensitivity to anti-EGFR therapy. Therapeutic resistance to EGFR blockade could be overcome in tumour graft models through combinatorial therapies targeting actionable genes. These analyses provide a systematic approach to evaluating response to targeted therapies in human cancer, highlight new mechanisms of responsiveness to anti-EGFR therapies, and delineate new avenues for intervention in managing colorectal cancer.

Portal Vein Ligation as an Efficient Method of Increasing the Future Liver Remnant Volume in the Surgical Treatment of Colorectal Metastases

OBJECTIVE To compare the volumetric increase of segments 2 and 3, segment 4, and the caudate lobe after portal vein ligation (PVL) and portal vein embolization (PVE). The small size of the remnant liver and chemotherapy-induced liver injury increase the risk of postoperative hepatic insufficiency after major hepatic resection for colorectal liver metastases. Portal vein ligation has been suggested to be less effective than embolization in inducing hypertrophy of the remnant liver. DESIGN, SETTING, AND PATIENTS We retrospectively reviewed 48 patients with colorectal liver metastases who underwent PVL (n = 17) or PVE (n = 31) at the Istituto per la Ricerca e la Cura del Cancro or the Institut Paoli-Calmette from March 1, 2000, through August 31, 2006. MAIN OUTCOME MEASURES To compare the volume increase of segments 2 and 3, segment 4, and of the caudate lobe in patients who have undergone PVL or PVE in preparation for a major hepatic resection. RESULTS There were no deaths related to PVE or PVL. Portal vein ligation was associated with resection of synchronous colorectal cancer in 16 patients. Resection of a liver metastasis in the remnant liver was performed in 11 patients. The median estimated baseline volume of segments 2 and 3 was 17.7% in the PVL group and 17.5% in the PVE group (P = .72). After PVL or PVE, it increased to 26.9% and 24.7%, respectively (P = .95), for volumetric increases of 43.1% and 53.4%, respectively (P = .39). The volumetric increases of segment 4 and the caudate lobe were similar. CONCLUSION Portal vein ligation is as effective as PVE in inducing hypertrophy of the remnant liver volume.

Inhibition of MEK and PI3K/mTOR Suppresses Tumor Growth but Does Not Cause Tumor Regression in Patient-Derived Xenografts of RAS-Mutant Colorectal Carcinomas

Purpose: Gene mutations along the Ras pathway (KRAS, NRAS, BRAF, PIK3CA) occur in approximately 50% of colorectal cancers (CRC) and correlate with poor response to anti–EGF receptor (EGFR) therapies. We assessed the effects of mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK) and phosphoinositide 3-kinase (PI3K)/mTOR inhibitors, which neutralize the major Ras effectors, in patient-derived xenografts from RAS/RAF/PIK3CA-mutant metastatic CRCs (mCRC). Experimental Design: Forty mCRC specimens harboring KRAS, NRAS, BRAF, and/or PIK3CA mutations were implanted in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Each xenograft was expanded into four treatment arms: placebo, the MEK inhibitor AZD6244, the PI3K/mTOR inhibitor, BEZ235, or AZD6244 + BEZ235. Cases initially treated with placebo crossed over to AZD6244, BEZ235, and the anti-EGFR monoclonal antibody cetuximab. Results: At the 3-week evaluation time point, cotreatment of established tumors with AZD6244 + BEZ235 induced disease stabilization in the majority of cases (70%) but did not lead to overt tumor regression. Monotherapy was less effective, with BEZ235 displaying higher activity than AZD6244 (disease control rates, DCRs: AZD6244, 27.5%; BEZ235, 42.5%). Triple therapy with cetuximab provided further advantage (DCR, 88%). The extent of disease control declined at the 6-week evaluation time point (DCRs: AZD6244, 13.9%; BEZ235, 16.2%; AZD6244 + BEZ235, 34%). Cross-analysis of mice harboring xenografts from the same original tumor and treated with each of the different modalities revealed subgroups with preferential sensitivity to AZD6244 (12.5%), BEZ235 (35%), or AZD6244 + BEZ235 (42.5%); another subgroup (10%) showed equivalent response to any treatment. Conclusions: The prevalent growth-suppressive effects produced by MEK and PI3K/mTOR inhibition suggest that this strategy may retard disease progression in patients. However, data offer cautionary evidence against the occurrence of durable responses. Clin Cancer Res; 18(9); 2515–25. ©2012 AACR.

Portal hypertension: contraindication to liver surgery?

IntroductionIn recent decades liver resection has become a safe procedure, mainly because of better patient selection. Despite this progress, however, outcomes of hepatectomy in cirrhotic patients with portal hypertension are still uncertain. The aim of this study was to elucidate early and long-term outcomes of liver resection in these patients.MethodsBetween 1985 and 2003, a total of 245 cirrhotic patients underwent hepatectomy for HCC. Altogether, 217 patients were eligible for this analysis and were divided into two groups according to the presence of portal hypertension at the time of surgery: 99 patients with portal hypertension and 118 without it.ResultsPatients with portal hypertension had worse preoperative liver function (Child-Pugh A class patients: 66.7% vs. 94.9%; P < 0.0001). No differences were encountered in terms of intraoperative and pathology data. Operative mortality was similar (11.1% vs. 5.1%; P = 0.100), but patients with portal hypertension had higher morbidity (43.4% vs. 30.5%; P = 0.049) and received a higher rate of blood and plasma transfusions (51.5% vs. 32.2%, P = 0.004; 77.8% vs. 57.6%, P = 0.0017). Considering only Child-Pugh A patients, short-term results were similar in the two groups in terms of mortality, morbidity, and transfusion rates. The 5-year survival rate was significantly higher in patients without portal hypertension (39.8% vs. 28.9%; P = 0.020), although when considering only Child-Pugh A patients no difference of survival was encountered. Multivariate analysis identified Child-Pugh classification, tumor diameter, and vascular invasion as independent predicting factors for survival.ConclusionsPortal hypertension should not be considered an absolute contraindication to hepatectomy in cirrhotic patients. Child-Pugh A patients with portal hypertension have short- and long-term results similar to patients with normal portal pressure.

Asymptomatic Colorectal Cancer with Un-Resectable Liver Metastases: Immediate Colorectal Resection or Up-Front Systemic Chemotherapy?

BackgroundAbout 20% of patients with colorectal cancer have synchronous un-resectable liver metastases. Resection of colorectal cancer in patients with moderate-severe symptoms is mandatory before starting chemotherapy. Surgical treatment of asymptomatic colorectal cancers is still a matter of discussion.MethodsFrom January 2000 to December 2004, we prospectively collected data on 35 consecutive patients who were treated straightaway by chemotherapy without primary tumor resection. All patients underwent FOLFOX6 as first-line chemotherapy. The aim of the study was to evaluate the rate of surgical complications related to un-resected colorectal tumor.ResultsThe mean interval between diagnosis and start of chemotherapy was 23.1 days (95% CI: 17.3–28.8). Fifteen of the 35 patients (42.9%) were down-staged to surgery; the mean interval between chemotherapy start and colon-rectum cancer resection was 6.5 months (95% CI: 5.5–7.5). None of them developed complications related to the primary tumor during chemotherapy. Of the other 20 patients who did not undergo any curative surgery, 16 received a second line chemotherapy and 10 a third line: six patients are alive and without intestinal symptoms (mean follow up 22.5 months, 95% CI: 11.2–33.9). Only one patient (2.8%) developed clinical signs of intestinal occlusion 5.6 months from the start of chemotherapy and required urgent colostomy.ConclusionsThe rate of complications related to the non-resected colorectal tumor is very low using oxaliplatin as first line chemotherapy. Non-operative management of asymptomatic colorectal cancers with un-resectable liver metastases is a safe approach.

Liver resection for hilar cholangiocarcinoma: in-hospital mortality and longterm survival

BACKGROUND Extended surgical procedures are the only chance of longterm survival for patients with Klatskin tumors, but high mortality rates have been reported. The type of treatment for Bismuth type l-II carcinomas is still a matter of discussion. STUDY DESIGN We performed a single-unit, retrospective study analyzing 36 patients who underwent resectional surgery for Klatskin tumor. RESULTS An associated liver resection was performed in 88.9% of our patients; most of them had a major hepatectomy. The in-hospital mortality rate was 2.8%. Three- and 5-year survival rates were 40.8% and 27.2%, respectively. But the group of patients with Bismuth type I-II carcinomas undergoing hepatectomy had markedly better longterm outcomes than those undergoing hilar resection (p = 0.04): 54.5% versus 0% at 5 years, respectively; none of the patients who had only resection of bile duct confluence were alive at 2 years. Lymph node metastases were found in 38.8% of our patients; nodal involvement was not a major prognostic factor. CONCLUSIONS Achievement of low in-hospital mortality rates is possible in specialized surgical departments. Aggressive surgical approaches can allow better longterm results in the subset of Bismuth type I-II carcinomas.

Genetic and Expression Analysis of MET, MACC1, and HGF in Metastatic Colorectal Cancer: Response to Met Inhibition in Patient Xenografts and Pathologic Correlations

Purpose: We determined the gene copy numbers for MET, for its transcriptional activator MACC1 and for its ligand hepatocyte growth factor (HGF) in liver metastases from colorectal carcinoma (mCRC). We correlated copy numbers with mRNA levels and explored whether gain and/or overexpression of MET and MACC1 predict response to anti-Met therapies. Finally, we assessed whether their genomic or transcriptional deregulation correlates with pathologic and molecular parameters of aggressive disease. Experimental Design: One hundred three mCRCs were analyzed. Copy numbers and mRNA were determined by quantitative PCR (qPCR). Thirty nine samples were implanted and expanded in NOD (nonobese diabetic)/SCID (severe combined immunodeficient) mice to generate cohorts that were treated with the Met inhibitor JNJ-38877605. In silico analysis of MACC1 targets relied on genome-wide mapping of promoter regions and on expression data from two CRC datasets. Results: No focal, high-grade amplifications of MET, MACC1, or HGF were detected. Chromosome 7 polysomy and gain of the p-arm were observed in 21% and 8% of cases, respectively, and significantly correlated with higher expression of both Met and MACC1. Met inhibition in patient-derived xenografts did not modify tumor growth. Copy number gain and overexpression of MACC1 correlated with unfavorable pathologic features better than overexpression of Met. Bioinformatic analysis of putative MACC1 targets identified elements besides Met, whose overexpression cosegregated with aggressive forms of colorectal cancer. Conclusions: Experiments in patient-derived xenografts suggest that mCRCs do not rely on Met genomic gain and/or overexpression for growth. On the basis of pathologic correlations and bioinformatic analysis, MACC1 could contribute to CRC progression through mechanisms other than or additional to Met transcriptional upregulation. Clin Cancer Res; 17(10); 3146–56. ©2011 AACR.

Hepatectomy as treatment of choice for hepatocellular carcinoma in elderly cirrhotic patients.

In recent decades liver resection has become a safe procedure; however, the outcome of hepatectomies in aged cirrhotic patients is often uncertain. To elucidate early and long-term outcomes of hepatectomy for HCC in the elderly, we studied 241 cirrhotic patients who underwent liver resection for HCC between 1985 and 2003. According to their age at the time of surgery, patients were divided into two groups: aged > 70 years (64 patients) and aged ≤ 70 years (177 patients). Operative mortality was 3.1% in the elderly and 9.6% in the younger group (p = 0.113). Postoperative morbidity and liver failure rates were higher in the younger group (42.4% versus 23.4%, p = 0.0073; 12.9% versus l.6%, p = 0.0065). Five-year survival rates are 48.6% in the elderly group and 32.3% in the younger group (p = 0.081). Considering only radical resections in Child-Pugh A patients, survival remains similar in the two groups (p = 0.072). Disease-free survival is not different in the two groups. A survival analysis performed according to the tumor diameter shows a better survival for elderly Child-Pugh A patients with HCC larger than 5 cm radically resected (50.8% versus 16.1% 5-year survival, p = 0.034). In univariate analysis, tumor size is not a prognostic factor in the elderly, whereas younger patients with large tumors have a worse outcome. Age by itself is not a contraindication for surgery, and selected cirrhotic patients with HCC who are 70 years of age or older could benefit from resection, even in the presence of large tumors. Long-term results of liver resections for HCC in the elderly may be even better than in younger patients.

Repeat hepatectomy for colorectal liver metastases: A worthwhile operation?

After curative resection of hepatic colorectal metastases, 10–20% of patients experience a resectable hepatic recurrence. We wanted to assess the expected risk‐to‐benefit ratio in comparison to first hepatectomy and to determine the prognostic factors associated with survival.