Is there a case for routine clinical application of ploidy measurements in gastrointestinal tumours?

Evaluating the Significance of Pancreatobiliary Fluorescence In Situ Hybridization Polysomy on Prognosis in De Novo Cholangiocarcinoma

INTRODUCTION

We recently developed a fluorescence in situ hybridization probe set for evaluating suspicious biliary and pancreatic duct strictures (PB-FISH). We aimed to determine whether PB-FISH results in biliary brush cytology specimens are associated with outcomes of patients with cholangiocarcinoma (CCA).

METHODS

We performed a retrospective study of patients with CCA tested by PB-FISH from January 2015 to August 2018. CCA was stratified by primary sclerosing cholangitis (PSC) into those with (PSC CCA) or without PSC ( de novo CCA). PB-FISH results were categorized as polysomy (gain of multiple loci), nonpolysomy (single locus gain, single locus gain with 9p21 loss, homozygous 9p21 loss, tetrasomy), and disomy (no abnormalities). Overall survival (OS) was estimated using Kaplan-Meier methods and compared between the PB-FISH results using log-rank tests. Cox models were adjusted for age, sex, CA 19-9, cytology results, source of brushing sample, and treatments.

RESULTS

Characteristics of 264 eligible patients (median age 60.4; range 18-92) were comparable for patients with PB-FISH polysomy vs nonpolysomy vs disomy. The median OS was similar between disomy, nonpolysomy, and polysomy in the overall population (22.7 vs 22.7 vs 20.3 months, respectively). For de novo CCA, both polysomy and nonpolysomy were associated with worse OS compared with disomy (polysomy: hazard ratio [HR] = 2.09, 95% confidence interval [CI] = 1.14-3.83; nonpolysomy: HR = 2.4, 95% CI = 0.54-2.46; P = 0.027). For PSC CCA, neither polysomy nor nonpolysomy were significantly associated with worse OS (polysomy: 0.90, 95% CI = 0.47-1.75; nonpolysomy: HR = 1.78, CI = 0.71-4.49; P = 0.27).

DISCUSSION

PB-FISH alterations are associated with worse survival in de novo CCA, though statistical significance was lost when adjusting for confounding variables.

Combining aneuploidy and dysplasia for colitis' cancer risk assessment outperforms current surveillance efficiency: a meta-analysis

PURPOSE

Cancer risk assessment for ulcerative colitis patients by evaluating histological changes through colonoscopy surveillance is still challenging. Thus, additional parameters of high prognostic impact for the development of colitis-associated carcinoma are necessary. This meta-analysis was conducted to clarify the value of aneuploidy as predictor for individual cancer risk compared with current surveillance parameters.

METHODS

A systematic web-based search identified studies published in English that addressed the relevance of the ploidy status for individual cancer risk during surveillance in comparison to neoplastic mucosal changes. The resulting data were included into a meta-analysis, and odds ratios (OR) were calculated for aneuploidy or dysplasia or aneuploidy plus dysplasia.

RESULTS

Twelve studies addressing the relevance of aneuploidy compared to dyplasia were comprehensively evaluated and further used for meta-analysis. The meta-analysis revealed that aneuploidy (OR 5.31 [95 % CI 2.03, 13.93]) is an equally effective parameter for cancer risk assessment in ulcerative colitis patients as dysplasia (OR 4.93 [1.61, 15.11]). Strikingly, the combined assessment of dysplasia and aneuploidy is superior compared to applying each parameter alone (OR 8.99 [3.08, 26.26]).

CONCLUSIONS

This meta-analysis reveals that aneuploidy is an equally effective parameter for individual cancer risk assessment in ulcerative colitis as the detection of dysplasia. More important, the combined assessment of dysplasia and aneuploidy outperforms the use of each parameter alone. We suggest image cytometry for ploidy assessment to become an additional feature of consensus criteria to individually assess cancer risk in UC.

MiR 21-5p as a predictor of recurrence in young gastric cancer patients

BACKGROUND AND AIM

It is generally assumed that gastric cancer (GC) in young patients has different clinicopathologic characteristics than that of elderly patients. Although recurrence is an important factor in determining prognosis, traditional clinicopathological factors are sometimes inadequate for predicting recurrence in individuals. Therefore, we aimed to identify miRNAs with the potential to predict recurrence in young patients.

METHODS

Young patients (age <40 years) undergoing gastrectomy for potentially curable GC (stage III) at Asan Medical Center participated in this study. A total of 50 GC patients with (n = 28) and without (n = 22) GC recurrence were selected for analysis. miRNA microarrays were analyzed to screen tissue samples (n = 7), and we validated the selected miRNAs by quantitative PCR in validation samples (n = 43).

RESULTS

Two miRNAs (hsa-miR-21-5p and hsa-miR-451a) identified in the microarray analysis were evaluated in the validation samples. Among the validation samples containing intratumoral stroma ≥ 70 (n = 35), hsa-miR-21-5p was more highly expressed in the recurrence group than in the nonrecurrence group (fold change 1.82, P = 0.03). In the validation samples with intratumoral stroma ≥ 70, the ΔCt of hsa-miR-21-5p, which was >3.35, had a sensitivity and specificity of 86.7% and 65.5%, respectively, for predicting recurrence, with an area under the ROC curve of 0.723.

CONCLUSIONS

miR-21-5p may be useful as a predictor of recurrence in young GC patients whose tumors contain a high proportion of intratumoral stroma. The combination of this miRNA with conventional clinicopathological factors should allow patient prognoses to be more accurately predicted.

Revisiting tumour aneuploidy - the place of ploidy assessment in the molecular era

Chromosome instability (CIN) is gaining increasing interest as a central process in cancer. CIN, either past or present, is indicated whenever tumour cells harbour an abnormal quantity of DNA, termed 'aneuploidy'. At present, the most widely used approach to detecting aneuploidy is DNA cytometry - a well-known research assay that involves staining of DNA in the nuclei of cells from a tissue sample, followed by analysis using quantitative flow cytometry or microscopic imaging. Aneuploidy in cancer tissue has been implicated as a predictor of a poor prognosis. In this Review, we have explored this hypothesis by surveying the current landscape of peer-reviewed research in which DNA cytometry has been applied in studies with disease-appropriate clinical follow up. This area of research is broad, however, and we restricted our survey to results published since 2000 relating to seven common epithelial cancers (those of the breast; endometrium, ovary, and uterine cervix; oesophagus; colon and rectum; lung; prostate; and bladder). We placed particular emphasis on results from multivariate analyses to pinpoint situations in which the prognostic value of aneuploidy as a biomarker is strong compared with that of existing indicators, such as clinical stage, histological grade, and specific molecular markers. We summarize the implications of our findings for the prognostic use of ploidy analysis in the clinic and for the theoretical understanding of the role of CIN in carcinogenesis.

Comprehensive genomic meta-analysis identifies intra-tumoural stroma as a predictor of survival in patients with gastric cancer

OBJECTIVE

Gastric adenocarcinoma (gastric cancer, GC) is a major cause of global cancer mortality. Identifying molecular programmes contributing to GC patient survival may improve our understanding of GC pathogenesis, highlight new prognostic factors and reveal novel therapeutic targets. The authors aimed to produce a comprehensive inventory of gene expression programmes expressed in primary GCs, and to identify those expression programmes significantly associated with patient survival.

DESIGN

Using a network-modelling approach, the authors performed a large-scale meta-analysis of GC transcriptome data integrating 940 gastric transcriptomes from multiple independent patient cohorts. The authors analysed a training set of 428 GCs and 163 non-malignant gastric samples, and a validation set of 288 GCs and 61 non-malignant gastric samples.

RESULTS

The authors identified 178 gene expression programmes ('modules') expressed in primary GCs, which were associated with distinct biological processes, chromosomal location patterns, cis-regulatory motifs and clinicopathological parameters. Expression of a transforming growth factor β (TGF-β) signalling associated 'super-module' of stroma-related genes consistently predicted patient survival in multiple GC validation cohorts. The proportion of intra-tumoural stroma, quantified by morphometry in tissue sections from gastrectomy specimens, was also significantly associated with stromal super-module expression and GC patient survival.

CONCLUSION

Stromal gene expression predicts GC patient survival in multiple independent cohorts, and may be closely related to the intra-tumoural stroma proportion, a specific morphological GC phenotype. These findings suggest that therapeutic approaches targeting the GC stroma may merit evaluation.

Gastric cancer pathology and underlying molecular mechanisms

The development of gastric adenocarcinoma is a complex multistep process involving multiple genetic alterations. Based on pathology, four different macroscopic types and at least two major histological types, intestinal and diffuse, have been described. Most gastric cancer (GC) show genetic instability, either microsatellite instability or chromosomal instability, which is considered an early event in gastric carcinogenesis. Molecular studies of alterations of single genes have provided evidence that intestinal and diffuse type GC evolve via different genetic pathways. Recent results from high-throughput whole-genome expression or copy number studies have demonstrated extensive genetic diversity between cases and within individual GC. Sets of commonly up- or downregulated microRNAs have been identified in GC and might be useful in the near future to identify pathways of GC progression. Results from detailed molecular and/or pathological GC studies, although promising, still have limited clinical utility in predicting survival and stratifying GC patients for appropriate treatment.

Gross genomic damage measured by DNA image cytometry independently predicts gastric cancer patient survival

Background:

DNA aneuploidy reflects gross genomic changes. It can be measured by flow cytometry (FCM-DNA) or image cytometry (ICM-DNA). In gastric cancer, the prevalence of DNA aneuploidy has been reported to range from 27 to 100%, with conflicting associations with clinicopathological variables. The aim of our study was to compare the DNA ploidy status measured using FCM-DNA and ICM-DNA in gastric cancer and to evaluate its association with clinicopathological variables.

Methods:

Cell nuclei were isolated from 221 formalin-fixed, paraffin-embedded gastric cancer samples. DNA ploidy was assessed using FCM-DNA and ICM-DNA.

Results:

A total of 178 (80.5%) gastric cancer samples were classified as DNA aneuploid using FCM-DNA, compared with 172 (77.8%) gastric cancer samples when using ICM-DNA. Results obtained from both methods were concordant in 183 (82.8%) cases (κ=0.48). Patients with ICM-DNA diploid gastric cancer survived significantly longer than those with ICM-DNA aneuploid gastric cancer (log rank 10.1, P=0.001). For FCM-DNA data, this difference did not reach statistical significance. The multivariate Cox model showed that ICM-DNA ploidy status predicted patient survival independently of tumour-node-metastasis status.

Conclusion:

ICM-DNA ploidy status is an independent predictor of survival in gastric cancer patients and may therefore be a more clinically relevant read out of gross genomic damage than FCM-DNA.

Aneuploidy involving chromosome 1 may be an early predictive marker of intestinal type gastric cancer

Intestinal type gastric cancer is a significant cause of mortality, therefore a better understanding of its molecular basis is required. We assessed if either aneuploidy or activity of the oncogenic transcription factor nuclear factor kappa B (NF-kappaB), increased incrementally during pre-malignant gastric histological progression and also if they correlated with each other in patient samples, as they are both induced by oxygen free radicals. In a prospective study of 54 (aneuploidy) and 59 (NF-kappaB) consecutive patients, aneuploidy was assessed by interphase fluorescent in situ hybridisation (FISH) for chromosome 1. NF-kappaB was assessed by expression of interleukin-8 (IL-8), and in a subset, by immunohistochemistry (IHC) for active p65. Aneuploidy levels increased incrementally across the histological series. 2.76% of cells with normal histology (95% CI, 2.14-3.38%) showed background levels of aneuploidy, this increased to averages of 3.78% (95% CI, 3.21-4.35%), 5.89% (95% CI, 3.72-8.06%) and 7.29% (95% CI, 4.73-9.85%) of cells from patients with gastritis, Helicobacter pylori positive gastritis and atrophy/intestinal metaplasia (IM) respectively. IL-8 expression was only increased in patients with current H. pylori infection. NF-kappaB analysis showed some increased p65 activity in inflamed tissues. IL-8 expression and aneuploidy level were not linked in individual patients. Aneuploidy levels increased incrementally during histological progression; were significantly elevated at very early stages of neoplastic progression and could well be linked to cancer development and used to assess cancer risk. Reactive oxygen species (ROS) induced in early gastric cancer are presumably responsible for the stepwise accumulation of this particular mutation, i.e. aneuploidy. Hence, aneuploidy measured by fluorescent in situ hybridisation (FISH) coupled to brush cytology, would be worthy of consideration as a predictive marker in gastric cancer and could be clinically useful in pre-malignant disease to stratify patients by their cancer risk.

Integrative genomics identifies RAB23 as an invasion mediator gene in diffuse-type gastric cancer

Recurrent genomic amplifications and deletions are frequently observed in primary gastric cancers (GC). However, identifying specific oncogenes and tumor suppressor genes within these regions can be challenging, as they often cover tens to hundreds of genes. Here, we combined high-resolution array-based comparative genomic hybridization (aCGH) with gene expression profiling to target genes within focal high-level amplifications in GC cell lines, and identified RAB23 as an amplified and overexpressed Chr 6p11p12 gene in Hs746T cells. High RAB23 protein expression was also observed in some lines lacking RAB23 amplification, suggesting additional mechanisms for up-regulating RAB23 besides gene amplification. siRNA silencing of RAB23 significantly reduced cellular invasion and migration in Hs746T cells, whereas overexpression of RAB23 enhanced cellular invasion in AGS cells. RAB23 amplifications in primary gastric tumors were confirmed by both fluorescence in situ hybridization and genomic qPCR, and in two independent patient cohorts from Hong Kong and the United Kingdom RAB23 expression was significantly associated with diffuse-type GC (dGC) compared with intestinal-type GC (iGC). These results provide further evidence that dGC and iGC likely represent two molecularly distinct tumor types, and show that investigating focal chromosomal amplifications by combining high-resolution aCGH with expression profiling is a powerful strategy for identifying novel cancer genes in regions of recurrent chromosomal aberration.

Predictive biomarkers of chemotherapy efficacy in colorectal cancer: results from the UK MRC FOCUS trial

PURPOSE

Candidate predictive biomarkers for irinotecan and oxaliplatin were assessed in 1,628 patients in Fluorouracil, Oxaliplatin, CPT-11: Use and Sequencing (FOCUS), a large randomized trial of fluorouracil alone compared with fluorouracil and irinotecan and compared with fluorouracil and oxaliplatin in advanced colorectal cancer.

METHODS

The candidate biomarkers were: tumor immunohistochemistry for MLH1/MSH2, p53, topoisomerase-1 (Topo1), excision repair cross-complementing gene 1 (ERCC1), O-6-methylguanine-DNA-methyltranserase (MGMT), and cyclooxygenase 2 (COX2); germline DNA polymorphisms in GSTP1, ABCB1, XRCC1, ERCC2, and UGT1A1. These were screened in more than 750 patients for interaction with benefit from irinotecan or oxaliplatin; two markers (Topo1 and MLH1/MSH2) met criteria to be taken forward for analysis in the full population. Primary end points were progression-free survival (PFS) and overall survival.

RESULTS

One thousand three hundred thirteen patients (81%) were assessable for Topo1 immunohistochemistry (low, < 10%; moderate, 10% to 50%; or high, > 50% tumor nuclei). In patients with low Topo1, PFS was not improved by the addition of either irinotecan (hazard ratio [HR], 0.98; 95% CI, 0.78 to 1.22) or oxaliplatin (HR, 0.85; 95% CI, 0.68 to 1.07); conversely, patients with moderate/high Topo1 benefited from the addition of either drug (HR, 0.48 to 0.70 in all categories; interaction P = .005; overall, P = .001 for irinotecan; P = .05 for oxaliplatin). High Topo1 was associated with a major overall survival benefit with first-line combination chemotherapy (HR, 0.60; median benefit, 5.3 months); patients with moderate or low Topo1 did not benefit (HR, 0.92 and 1.09, respectively; interaction P = .005). MLH1/MSH2 did not show significant interaction with treatment, although the low rate of loss (4.4%) limits the power of the study for this biomarker.

CONCLUSION

Topo1 immunohistochemistry identified subpopulations that did or did not benefit from irinotecan, and possibly also from oxaliplatin. If verified independently, this information will contribute to the individualization of treatment for colorectal cancer.

Comparison of DNA histograms by standard flow cytometry and image cytometry on sections in Barrett's adenocarcinoma

Background

The purpose of this study was to compare DNA histograms obtained by standard flow cytometry (FC) and high fidelity image cytometry on sections (ICS) in normal gastrointestinal mucosa and Barrett's adenocarcinoma (BAC).

Conclusion

ICS detects DNA aneuploidy in all BAC samples while FC missed the diagnosis of aneuploidy in 29%. In addition, ICS provides more information on HI and G2 exceeding rates.