Elizabeth K. Broussard

TNM Staging in Colorectal Cancer: T Is for T Cell and M Is for Memory

Immune cell infiltration is a common feature of many human solid tumors. Recently, increased infiltration of tumors with cytotoxic CD8-positive T cells has been correlated with prolonged survival in multivariate analyses in a variety of epithelial cell cancers, including small-cell lung carcinoma; carcinomas of the endomentrium, bile duct, esophagus, and urothelium; pancreatic adenocarcinoma; and hepatocellular carcinomas. In this issue of Journal of Clinical Oncology, Mlecnik et al suggest that immune cell infiltration of colorectal cancer by cytotoxic CD8-positive and memory CD45ROpositive T cells has prognostic discriminatory power that is superior to standard staging systems (ie, American Joint Committee on Cancer– International Union Against Cancer–TNM). The authors examined more than 400 patients with colorectal cancer, quantitated the density of tumor-infiltrating T cells, devised an immune scoring system (higher scores reflecting greater CD8-positive and CD45RO-positive T-cell density), and correlated the immune scores with clinical outcome. The results demonstrate two key findings: patients with high immune scores have increased disease-free and overall survival as compared with patients whose tumors demonstrate low immune scores, and the immune score was superior in predicting disease outcome as compared with a host of important prognostic clinical parameters, including TNM staging. The authors further observed that there was an inverse correlation between immune cell density and tumor stage. In patient samples with the greatest immune cell density, the majority (60%) were tumor in situ or T1 stage tumors. In contrast, only 18% of T4 tumors demonstrated high-density T-cell infiltrates. Moreover, there were no tumor in situ or T1 stage disease specimens showing weak immune cell density scores, whereas 45% of T4 tumors demonstrated low immune scores. The data suggest that even with minimal tumor invasion, patients with a low immune score will be likely to experience a disease relapse. For these patients, surgery may not be curative. Remarkably, the prognostic significance of the immune score was retained regardless of whether the tumor tissue was derived from a patient with stage I or stage IV colorectal cancer. The study by Mlecnik et al is the culmination of several observations this investigative group has made over the last few years. Their initial observation, that a high density of memory CD8-positive T cells was associated with decreased evidence of early metastasis and increased survival in colorectal cancer, was followed by the development of an immune gene signature, associated with type I adaptive immunity, that correlated with decreased cancer recurrence. Moreover, in the same study, the investigators demonstrated that the type, density, and location of the T-cell infiltrate in the tumor were prognostically important. Further evaluations defined the importance of the memory T-cell phenotype and demonstrated the loss of coordinated functional immunity with the evolution of the tumor to a metastatic phenotype. A focused investigation of patients with earlystage colorectal cancer suggested that a multimarker panel of CD45RO-positive and CD8-positive T cells and cytotoxicity-related genes could predict prognosis even in these patients with minimal disease. Taken together, these studies laid the foundation for the immune score presented by Mlecnik et al as a clinical prognostic marker at any stage of colorectal cancer. Is the immune score presented in the Mlecnik et al study definitive? There are a few issues that remain to be addressed. The first issue is a better definition of the contribution of T regulatory cells to an immune score in colorectal cancer. CD4-positive T regulatory cells, as assessed by FOXP3 expression, have been shown to potentially modulate the antitumor response by suppressing the activity of CD8positive cytotoxic T cells and have been demonstrated to be a prognostic marker for disease outcome in several types of cancers. A high density of intratumoral FOXP3-positive T regulatory cells has been associated with poor outcomes in multiple solid tumors, including ovarian, pancreatic, and hepatocellular carcinoma. However, in colorectal cancer, studies of infiltrating FOXP3-expressing cells suggest the opposite: that regulatory T cells in the tumor are associated with an improved prognosis. Investigators evaluating nearly 1,000 tumor specimens from patients with stages II and III colorectal cancer demonstrated in multivariate analysis that highdensity intratumoral FOXP3-positive T cells were associated with improved survival (P .001). In a much smaller evaluation of 40 colorectal cancers, increased intratumoral T regulatory cells were correlated with limited versus metastatic disease. An additional study assessed the tumors of approximately 50 patients with relapsed colorectal cancer undergoing chemotherapy, and found that high intratumoral FOXP3-positive T-cell infiltrate was associated with benefits in overall survival (P .0005) and progression-free survival (P .0009). Colorectal cancer may be uniquely suited to a beneficial prognostic response to infiltrating T regulatory cells. In states of chronic gastrointestinal inflammation, such as inflammatory bowel disease, absolute mucosal T regulatory cell numbers are increased as a JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L S VOLUME 29 NUMBER 6 FEBRUARY 2

The Long-term Efficacy and Safety of Fecal Microbiota Transplant for Recurrent, Severe, and Complicated Clostridium difficile Infection in 146 Elderly Individuals.

Objectives:Clostridium difficile infection (CDI) in the elderly has a higher prevalence, greater morbidity and mortality, and lower response to conventional treatment than the general population. Fecal microbiota transplant (FMT) is highly effective therapy for CDI but has not been studied specifically in the elderly. This study aims to determine the long-term efficacy and safety of FMT for recurrent (RCDI), severe (SCDI), and complicated (CCDI) CDI in elderly patients. Methods:A multicenter, long-term follow-up study was performed with demographic, pre-FMT, and post-FMT data collected from elderly patients with RCDI, SCDI, and CCDI, through a 47-item questionnaire. Outcome measures included primary and secondary cure rates, early (<12 wk) and late (≥12 wk) recurrence rates, and adverse events (AEs), including post-FMT diagnoses. Results:Of 168 eligible patients, 146 patients met the inclusion criteria. Of these, 68.5% were women. The mean (range) age was 78.6 (65 to 97) years and the follow-up period was 12.3 (1 to 48) months. FMT was performed for RCDI in 89 (61%), SCDI in 45 (30.8%), and CCDI in 12 (8.2%) patients. The primary and secondary cure rates were 82.9% and 95.9%, respectively. Early and late recurrences occurred in 25 and 6 patients, respectively. AEs included CDI-negative diarrhea in 7 (4.8%) and constipation in 4 (2.7%) patients. Serious AEs, recorded in 6 patients, were hospital admissions for CDI-related diarrhea, one of which culminated in death. New diagnoses post-FMT included microscopic colitis (2), Sjogren syndrome (1), follicular lymphoma (1), contact dermatitis and idiopathic Bence-Jones proteinuria (1), and laryngeal carcinoma (1)—all, however, were associated with predisposing factors. Conclusions:FMT is a safe and effective treatment option for RCDI, SCDI, and CCDI in elderly patients.

Fecal microbiota transplantation and donor standardization

Clostridium difficile diarrhea is a common and severe infectious disease. Antibiotics, which are standard initial treatment, are less effective for treating refractory or recurrent infection. Fecal microbiota transplantation, where healthy donor stool is transplanted into a patient, is an alternative to antibiotic therapy that requires standardization for donors and patients.

Associations among gut permeability, inflammatory markers, and symptoms in patients with irritable bowel syndrome.

BackgroundAlterations in gastrointestinal (GI) permeability and immune measures are present in some patients with irritable bowel syndrome (IBS) but the relationship to symptoms is poorly defined. In adults with IBS, we compared permeability, unstimulated peripheral blood monocyte (PBMC) interleukin-10 (IL-10) levels, IBS life interference, and GI and psychological distress symptoms.MethodsIn 88 women and 18 men with IBS, GI permeability was quantitated as percent recovery of urinary sucrose and the lactulose/mannitol (L/M) ratio. IL-10 was measured in supernatants from 72-h incubated, unstimulated PBMCs. Participants completed a 4-week daily diary recording IBS life interference on daily activities and work, IBS symptoms, and psychological distress symptoms. They also completed the Brief Symptom Inventory.ResultsThe L/M ratio but not percent sucrose recovery was significantly correlated with IBS interference with activities and work and retrospectively measured anxiety and depression. Unstimulated PBMC production of IL-10 correlated significantly with IBS interference with daily work, IBS symptom score, and abdominal pain. We identified a subgroup of IBS subjects with higher IL-10 and/or higher L/M ratio who had substantially higher IBS interference and IBS symptom scores.ConclusionsOur findings suggest a distinct subgroup of IBS patients with alterations in gut barrier function. This subgroup is characterized by increased GI permeability and/or increased PBMC production of IL-10. These physiologic alterations reflect more severe IBS as measured by interference of IBS with daily activities and daily IBS symptoms.

Alteration of the intestinal microbiome: fecal microbiota transplant and probiotics for Clostridium difficile and beyond.

Clostridium difficile infection is increasingly common with a high risk of recurrence despite antibiotic treatment. In cases of recurrent C. difficile infection, fecal microbiota transplant (FMT) is a highly effective treatment option promoting the restoration of normal gut microbiota. Furthermore, preliminary uncontrolled evidence demonstrates possible benefit of FMT in the management of some cases of inflammatory bowel disease and chronic constipation. In addition to presenting an overview of FMT, we discuss the role of probiotics, a more common approach to modifying the intestinal microbiome. Probiotics have been utilized broadly for many disease processes, including gastrointestinal, cardiovascular and allergic disease settings, although with limited and inconsistent results. Multiple potential areas for research are also identified.

Fecal microbiota transplantation: current clinical efficacy and future prospects.

Fecal microbiota transplantation (FMT) has gained mainstream attention with its remarkable efficacy in treating recurrent Clostridium difficile infection (RCDI) when there are no other effective therapies. Methods of selecting donors and routes of administration vary among studies, but there are now randomized controlled trials showing efficacy of FMT in treating RCDI. Ongoing trials of FMT for other disease such as inflammatory bowel disease are underway; this therapy should not be used for these conditions unless there is strong evidence for efficacy. Long-term safety data are sorely needed, as well as clarification of regulatory concerns.

Identification of Putative Immunologic Targets for Colon Cancer Prevention Based on Conserved Gene Upregulation from Preinvasive to Malignant Lesions

The length of time required for preinvasive adenoma to progress to carcinoma, the immunogenicity of colorectal cancer (CRC), and the identification of high-risk populations make development and testing of a prophylactic vaccine for the prevention of CRC possible. We hypothesized that genes upregulated in adenoma relative to normal tissue, which maintained increased expression in CRC, would encode proteins suitable as putative targets for immunoprevention. We evaluated existing adenoma and CRC microarray datasets and identified 160 genes that were ≥2-fold upregulated in both adenoma and CRC relative to normal colon tissue. We further identified 23 genes that showed protein overexpression in colon adenoma and CRC based on literature review. Silencing the most highly upregulated genes, CDH3, CLDN1, KRT23, and MMP7, in adenoma and CRC cell lines resulted in a significant decrease in viability (P < 0.0001) and proliferation (P < 0.0001) as compared to controls and an increase in cellular apoptosis (P < 0.05 for CDH3, KRT23). Results were duplicated across cell lines representing microsatellite instability, CpG island methylator, and chromosomal instability phenotypes, suggesting immunologic elimination of cells expressing these proteins could impact the progression of all CRC phenotypes. To determine whether these proteins were immunogens, we interrogated sera from early stage CRC patients and controls and found significantly elevated CDH3 (P = 0.006), KRT23 (P = 0.0007), and MMP7 (P < 0.0001) serum immunoglobulin G in cases as compared to controls. These data show a high throughput approach to the identification of biologically relevant putative immunologic targets for CRC and identified three candidates suitable for vaccine development. Cancer Prev Res; 6(7); 666–74. ©2013 AACR.

Perioperative Glycemic Control During Colorectal Surgery

Hyperglycemia occurs frequently among patients undergoing colorectal surgery and is associated with increased risk of poor clinical outcomes, especially related to surgical site infections. Treating hyperglycemia has become a target of many enhanced recovery after surgery programs developed for colorectal procedures. There are several unique considerations for patients undergoing colorectal surgery including bowel preparations and alterations in oral intake. Focused protocols for those with diabetes and those at risk of hyperglycemia are needed in order to address the specific needs of those undergoing colorectal procedures.

Clinical Application of Plasmid-Based Cancer Vaccines

Decades of work on DNA-based cancer vaccination has produced numerous clinical candidates, most targeting single tumor-associated antigens, a few targeting multiple antigens or epitopes, and virtually all predominantly aimed at the induction of CD8+ cytotoxic T cells. Clinical trials in melanoma, prostate, breast, colorectal, and cervical carcinomas reporting results in the past few years are herein reviewed. Clinical and immunological responses were generally small and detected in only a minority of patients. High doses, extended immunization periods, and multifaceted platforms have modestly improved immunogenicity. Appreciating the important role polyfunctional CD4+ helper T cells play in tumor rejection, and using recent advances in epitope mapping and informatics, a new generation of DNA-based vaccines targeting CD4+ epitopes that are both tumor reactive and bind multiple MHC class II haplotypes are now entering clinical trials. With such an empirical approach, DNA-based vaccines may be poised to become potent weapons in the armamentarium against cancer.

High prevalence of Helicobacter pylori clarithromycin resistance mutations among Seattle patients measured by droplet digital PCR

Treatment of Helicobacter pylori infection is often empiric; however, current guidelines for management of Helicobacter pylori infection advise against the use of standard triple therapy (clarithromycin, amoxicillin, and proton‐pump inhibitor) when clarithromycin resistance exceeds 20%. We developed and tested a new culture‐free assay to detect clarithromycin resistance‐conferring mutations to determine the prevalence of H. pylori clarithromycin resistance in patients from the United States Pacific Northwest.