Mucin expression in gastric- and gastro-oesophageal signet-ring cell cancer: results from a comprehensive literature review and a large cohort study of Caucasian and Asian gastric cancer.

BACKGROUND: The literature on the prognostic relevance of signet-ring cell (SRC) histology in gastric cancer (GC) is controversial which is most likely related to inconsistent SRC classification based on haematoxylin-eosin staining. We hypothesised that mucin stains can consistently identify SRC-GC and predict GC patient outcome. METHODS: We performed a comprehensive literature review on mucin stains in SRC-GC and characterised the mucin expression in 851 Caucasian GC and 410 Asian GC using Alcian Blue (AB)-Periodic Acid-Schiff (PAS), MUC2 (intestinal-type mucin), and MUC5AC (gastric-type mucin). The relationship between mucin expression and histological phenotype [poorly cohesive (PC) including proportion of SRCs, non-poorly cohesive (non-PC), or mucinous (MC)], clinicopathological variables, and patient outcome was analysed. RESULTS: Depending on mucin expression and cut-offs, the positivity rates of SRC-GC reported in the literature varied from 6 to 100%. Patients with MUC2 positive SRC-GC or SRC-GC with (gastro)intestinal phenotype had poorest outcome. In our cohort study, PC with ≥ 10% SRCs expressed more frequently MUC2, MUC5AC, and ABPAS (p < 0.001, p = 0.004 and p < 0.001, respectively). Caucasians with AB positive GC or combined ABPAS-MUC2 positive and MUC5AC negative had poorest outcome (all p = 0.002). This association was not seen in Asian patients. CONCLUSIONS: This is the first study to suggest that mucin stains do not help to differentiate between SRC-GC and non-SRC-GC. However, mucin stains appear to be able to identify GC patients with different outcome. To our surprise, the relationship between outcome and mucin expression seems to differ between Caucasian and Asian GC patients which warrants further investigations.

Quality assurance of surgery in the randomized ST03 trial of perioperative chemotherapy in carcinoma of the stomach and gastro-oesophageal junction.

BACKGROUND: The UK Medical Research Council ST03 trial compared perioperative epirubicin, cisplatin and capecitabine (ECX) chemotherapy with or without bevacizumab (B) in gastric and oesophagogastric junctional cancer. No difference in survival was noted between the arms of the trial. The present study reviewed the standards and performance of surgery in the context of the protocol-specified surgical criteria. METHODS: Surgical and pathological clinical report forms were reviewed to determine adherence to the surgical protocols, perioperative morbidity and mortality, and final histopathological stage for all patients treated in the study. RESULTS: Of 1063 patients randomized, 895 (84·2 per cent) underwent resection; surgical details were available for 880 (98·3 per cent). Postoperative assessment data were available for 873 patients; complications occurred in 458 (52·5 per cent) overall, of whom 71 (8·1 per cent) developed complications deemed to be life-threatening by the responsible clinician. The most common complications were respiratory (211 patients, 24·2 per cent). The anastomotic leak rate was 118 of 873 (13·5 per cent) overall; among those who underwent oesophagogastrectomy, the rate was higher in the group receiving ECX-B (23·6 per cent versus 9·9 per cent in the ECX group). Pathological assessment data were available for 845 patients. At least 15 nodes were removed in 82·5 per cent of resections and the median lymph node harvest was 24 (i.q.r. 17-34). Twenty-five or more nodes were removed in 49·0 per cent of patients. Histopathologically, the R1 rate was 24·9 per cent (208 of 834 patients). An R1 resection was more common for proximal tumours. CONCLUSION: In the ST03 trial, the performance of surgery met the protocol-stipulated criteria. Registration number: NCT00450203 ( http://www.clinicaltrials.gov).

Consensus on the pathological definition and classification of poorly cohesive gastric carcinoma.

BACKGROUND AND AIMS: Clinicopathological characteristics of gastric cancer (GC) are changing, especially in the West with a decreasing incidence of distal, intestinal-type tumours and the corresponding increasing proportion of tumours with Laurén diffuse or WHO poorly cohesive (PC) including signet ring cell (SRC) histology. To accurately assess the behaviour and the prognosis of these GC subtypes, the standardization of pathological definitions is needed. METHODS: A multidisciplinary expert team belonging to the European Chapter of International Gastric Cancer Association (IGCA) identified 11 topics on pathological classifications used for PC and SRC GC. The topics were debated during a dedicated Workshop held in Verona in March 2017. Then, through a Delphi method, consensus statements for each topic were elaborated. RESULTS: A consensus was reached on the need to classify gastric carcinoma according to the most recent edition of the WHO classification which is currently WHO 2010. Moreover, to standardize the definition of SRC carcinomas, the proposal that only WHO PC carcinomas with more than 90% poorly cohesive cells having signet ring cell morphology have to be classified as SRC carcinomas was made. All other PC non-SRC types have to be further subdivided into PC carcinomas with SRC component (< 90% but > 10% SRCs) and PC carcinomas not otherwise specified (< 10% SRCs). CONCLUSION: The reported statements clarify some debated topics on pathological classifications used for PC and SRC GC. As such, this consensus classification would allow the generation of evidence on biological and prognostic differences between these GC subtypes.

Correction to: Consensus on the pathological definition and classification of poorly cohesive gastric carcinoma.

The authors would like to correct the error in the publication of the original article. The surname and given names of the authors were swapped in the "Acknowledgements". The corrected detail is given below.

Acetone clearance of mesocolic or mesorectal fat increases lymph node yield and may improve detection of high-risk Stage II colorectal cancer patients.

AIM: Lymph node (LN) status is key to determining the need for adjuvant therapy in colorectal cancer (CRC) and for disease which has progressed to Stage II (T3-T4, N0, M0). A yield of fewer than 12 LNs is considered a risk factor similar to high-grade histology and vascular, lymphatic and perineural invasion. The aim of this retrospective study was to investigate the effect of acetone fat clearance of the mesocolon or mesorectum on LN yield and the identification of patients with high-risk Stage II CRC. METHOD: After conventional LN retrieval, fatty tissue derived from the mesocolon or mesorectum of 80 CRC specimens was incubated in acetone for 24 h. A second dissection was then performed by a trained technician. The total number of LNs as well as tumour involvement (LNpositive and LNnegative) were assessed at each stage. In addition, LN morphology was assessed and clinicopathological data were extracted from existing pathology reports. RESULTS: Eighty CRC specimens were available for study. 1548 (94%) LN were negative and 96 (6%) were positive. The median (range) LN yield per specimen was 12 (3-41) LN increasing to 18 (4-48) LN after fat clearance (P < 0.001). After fat clearance, 534 additional LNs were identified in 75 (94%) of the specimens, and all but 10 were negative. The pN stage did not change in six patients who were found to be LN positive after fat clearance. However, the number of high-risk Stage II CRC patients decreased from 11 to 7. Although important for these patients, this downstaging did not reach statistical significance (P = 0.125). CONCLUSION: Acetone clearance of mesocolic or mesorectal fat increases median LN yield and may in a larger study decrease the number of patients classified as having high-risk Stage II CRC.

Cervical esophageal cancer: a gap in cancer knowledge.

BACKGROUND: The aim of this systematic review is to provide an overview of the diagnosis, treatment options and treatment-related complications of cervical esophageal carcinoma (CEC) and to subsequently provide recommendations to improve quality of care. DESIGN: Studies were identified in PubMed, EMBASE and Web of Science. A total of 107 publications fulfilled the inclusion criteria and were included. RESULTS: CEC is uncommon, accounting for 2%-10% of all esophageal carcinomas. These tumors are often locally advanced at presentation and have a poor prognosis, with a 5-year overall survival of 30%. Tobacco and alcohol consumption seem to be the major risk factors for developing CEC. Surgery is usually not possible due to the very close relationship to other organs such as the larynx, trachea and thyroid gland. Therefore, the current standard of care is definitive chemoradiation (dCRT) with curative intent. Treatment regimens used to treat CEC are adapted by established regimens in lower esophageal squamous cell carcinoma and head and neck squamous cell carcinoma. However, dCRT may be accompanied by severe side-effects and complications. Several diagnostic and predictive markers have been studied, but currently, there is no other biomarker than clinical stage to determine patient management. Suggestions to improve patient outcomes are to determine the exact radiation dose needed for adequate locoregional control and to combine radiotherapy with optimal systemic therapy backbone. CONCLUSION: CEC remains unchartered territory for many practising physicians and patients with CEC have a poor prognosis. To improve the outcome for CEC patients, future studies should focus on the identification of new diagnostic biomarkers or targets for radiosensitizers, amelioration of radiation schedules, optimal combination of chemotherapeutic agents and/or new therapeutic targets.

Brain metastases in gastro-oesophageal adenocarcinoma: insights into the role of the human epidermal growth factor receptor 2 (HER2).

BACKGROUND: Gastro-oesophageal adenocarcinomas rarely metastasize to the central nervous system (CNS). The role of the human epidermal growth factor receptor 2 (HER2) in patients with these cancers and CNS involvement is presently unknown. PATIENTS AND METHODS: A multicentre registry was established to collect data from patients with gastro-oesophageal adenocarcinomas and CNS involvement both retrospectively and prospectively. Inclusion in the study required a predefined clinical data set, a central neuro-radiological or histopathological confirmation of metastatic CNS involvement and central assessment of HER2 by immunohistochemistry (IHC) and in situ hybridisation (ISH). In addition, expression of E-cadherin and DNA mismatch repair (MMR) proteins were assessed by IHC. RESULTS: One hundred patients fulfilled the inclusion criteria. The population's median age was 59 years (interquartile range: 54-68), of which 85 (85%) were male. Twenty-five patients were of Asian and 75 of Caucasian origin. HER2 status was positive in 36% (95% CI: 26.6-46.2) of cases. Median time from initial diagnosis to the development of brain metastases (BMets) or leptomeningeal carcinomatosis (LC) was 9.9 months (95% CI: 8.5-15.0). Median overall survival from diagnosis was 16.9 months (95% CI: 14.0-20.7) and was not related to the HER2 status. E-cadherin loss was observed in 9% of cases and loss of expression in at least one DNA MMR proteins in 6%. CONCLUSIONS: The proportion of a positive HER2 status in patients with gastro-oesophageal adenocarcinoma and CNS involvement was higher than expected. The impact of anti-HER2 therapies should be studied prospectively.

FGFR2 amplification has prognostic significance in gastric cancer: results from a large international multicentre study.

BACKGROUND: In preclinical gastric cancer (GC) models, FGFR2 amplification was associated with increased tumour cell proliferation and survival, and drugs targeting this pathway are now in clinical trials. METHODS: FGFR2 FISH was performed on 961 GCs from the United Kingdom, China and Korea, and the relationship with clinicopathological data and overlap with HER2 amplification were analysed. RESULTS: The prevalence of FGFR2 amplification was similar between the three cohorts (UK 7.4%, China 4.6% and Korea 4.2%), and intratumoral heterogeneity was observed in 24% of FGFR2 amplified cases. FGFR2 amplification was associated with lymph node metastases (P<0.0001). FGFR2 amplification and polysomy were associated with poor overall survival (OS) in the Korean (OS: 1.83 vs 6.17 years, P=0.0073) and UK (OS: 0.45 vs 1.9 years, P<0.0001) cohorts, and FGFR2 amplification was an independent marker of poor survival in the UK cohort (P=0.0002). Co-amplification of FGFR2 and HER2 was rare, and when high-level amplifications did co-occur these were detected in distinct areas of the tumour. CONCLUSION: A similar incidence of FGFR2 amplification was found in Asian and UK GCs and was associated with lymphatic invasion and poor prognosis. This study also shows that HER2 and FGFR2 amplifications are mostly exclusive.

Tumour expression of leptin is associated with chemotherapy resistance and therapy-independent prognosis in gastro-oesophageal adenocarcinomas.

BACKGROUND: Cytotoxic chemotherapy remains the main systemic therapy for gastro-oesophageal adenocarcinoma, but resistance to chemotherapy is common, resulting in ineffective and often toxic treatment for patients. Predictive biomarkers for chemotherapy response would increase the probability of successful therapy, but none are currently recommended for clinical use. We used global gene expression profiling of tumour biopsies to identify novel predictive biomarkers for cytotoxic chemotherapy. METHODS: Tumour biopsies from patients (n=14) with TNM stage IB-IV gastro-oesophageal adenocarcinomas receiving platinum-based combination chemotherapy were used as a discovery cohort and profiled with Affymetrix ST1.0 Exon Genechips. An independent cohort of patients (n=154) treated with surgery with or without neoadjuvant platinum combination chemotherapy and gastric adenocarcinoma cell lines (n=22) were used for qualification of gene expression profiling results by immunohistochemistry. A cisplatin-resistant gastric cancer cell line, AGS Cis5, and the oesophageal adenocarcinoma cell line, OE33, were used for in vitro validation investigations. RESULTS: We identified 520 genes with differential expression (Mann-Whitney U, P<0.020) between radiological responding and nonresponding patients. Gene enrichment analysis (DAVID v6.7) was used on this list of 520 genes to identify pathways associated with response and identified the adipocytokine signalling pathway, with higher leptin mRNA associated with lack of radiological response (P=0.011). Similarly, in the independent cohort (n=154), higher leptin protein expression by immunohistochemistry in the tumour cells was associated with lack of histopathological response (P=0.007). Higher leptin protein expression by immunohistochemistry was also associated with improved survival in the absence of neoadjuvant chemotherapy, and patients with low leptin protein-expressing tumours had improved survival when treated by neoadjuvant chemotherapy (P for interaction=0.038). In the gastric adenocarcinoma cell lines, higher leptin protein expression was associated with resistance to cisplatin (P=0.008), but not to oxaliplatin (P=0.988) or 5fluorouracil (P=0.636). The leptin receptor antagonist SHLA increased the sensitivity of AGS Cis5 and OE33 cell lines to cisplatin. CONCLUSIONS: In gastro-oesophageal adenocarcinomas, tumour leptin expression is associated with chemoresistance but a better therapy-independent prognosis. Tumour leptin expression determined by immunohistochemistry has potential utility as a predictive marker of resistance to cytotoxic chemotherapy, and a prognostic marker independent of therapy in gastro-oesophageal adenocarcinoma. Leptin antagonists have been developed for clinical use and leptin and its associated pathways may also provide much needed novel therapeutic targets for gastro-oesophageal adenocarcinoma.

Stroma AReactive Invasion Front Areas (SARIFA): a novel histopathologic biomarker in colorectal cancer patients and its association with the luminal tumour proportion.

BACKGROUND: Stroma AReactive Invasion Front Areas (SARIFA) is a novel prognostic histopathologic biomarker measured at the invasive front in haematoxylin & eosin (H&E) stained colon and gastric cancer resection specimens. The aim of the current study was to validate the prognostic relevance of SARIFA-status in colorectal cancer (CRC) patients and investigate its association with the luminal proportion of tumour (PoT). METHODS: We established the SARIFA-status in 164 CRC resection specimens. The relationship between SARIFA-status, clinicopathological characteristics, recurrence-free survival (RFS), cancer-specific survival (CSS), and PoT was investigated. RESULTS: SARIFA-status was positive in 22.6% of all CRCs. SARIFA-positivity was related to higher pT, pN, pTNM stage and high grade of differentiation. SARIFA-positivity was associated with shorter RFS independent of known prognostic factors analysing all CRCs (RFS: hazard ratio (HR) 2.6, p = 0.032, CSS: HR 2.4, p = 0.05) and shorter RFS and CSS analysing only rectal cancers. SARIFA-positivity, which was measured at the invasive front, was associated with PoT-low (p = 0.009), e.g., higher stroma content, and lower vessel density (p = 0.0059) measured at the luminal tumour surface. CONCLUSION: Here, we validated the relationship between SARIFA-status and prognosis in CRC patients and provided first evidence for a potential prognostic relevance in the subgroup of rectal cancer patients. Interestingly, CRCs with different SARIFA-status also showed histological differences measurable at the luminal tumour surface. Further studies to better understand the relationship between high luminal intratumoural stroma content and absence of a stroma reaction at the invasive front (SARIFA-positivity) are warranted and may inform future treatment decisions in CRC patients.

An investigation of the clinical impact and therapeutic relevance of a DNA damage immune response (DDIR) signature in patients with advanced gastroesophageal adenocarcinoma.

BACKGROUND: An improved understanding of which gastroesophageal adenocarcinoma (GOA) patients respond to both chemotherapy and immune checkpoint inhibitors (ICI) is needed. We investigated the predictive role and underlying biology of a 44-gene DNA damage immune response (DDIR) signature in patients with advanced GOA. MATERIALS AND METHODS: Transcriptional profiling was carried out on pretreatment tissue from 252 GOA patients treated with platinum-based chemotherapy (three dose levels) within the randomized phase III GO2 trial. Cross-validation was carried out in two independent GOA cohorts with transcriptional profiling, immune cell immunohistochemistry and epidermal growth factor receptor (EGFR) fluorescent in situ hybridization (FISH) (n = 430). RESULTS: In the GO2 trial, DDIR-positive tumours had a greater radiological response (51.7% versus 28.5%, P = 0.022) and improved overall survival in a dose-dependent manner (P = 0.028). DDIR positivity was associated with a pretreatment inflamed tumour microenvironment (TME) and increased expression of biomarkers associated with ICI response such as CD274 (programmed death-ligand 1, PD-L1) and a microsatellite instability RNA signature. Consensus pathway analysis identified EGFR as a potential key determinant of the DDIR signature. EGFR amplification was associated with DDIR negativity and an immune cold TME. CONCLUSIONS: Our results indicate the importance of the GOA TME in chemotherapy response, its relationship to DNA damage repair and EGFR as a targetable driver of an immune cold TME. Chemotherapy-sensitive inflamed GOAs could benefit from ICI delivered in combination with standard chemotherapy. Combining EGFR inhibitors and ICIs warrants further investigation in patients with EGFR-amplified tumours.

KRAS and BRAF mutations are rare and related to DNA mismatch repair deficiency in gastric cancer from the East and the West: results from a large international multicentre study.

BACKGROUND: Inhibitors of the epidermal growth factor (EGFR) signaling pathway have a major role in the treatment of KRAS wild-type colorectal cancer patients. The EGFR pathway has been shown to be activated in gastric cancer (GC). However, published data on KRAS and BRAF mutation status is limited in GC and has not been compared between GC from different geographic regions. METHODS: The prevalence of KRAS and BRAF mutations was established in 712 GC: 278 GC from the United Kingdom, 230 GC from Japan and 204 GC from Singapore. The relationship between KRAS/BRAF mutation status, DNA mismatch repair (MMR) status, clinicopathological variables and overall survival was analysed. RESULTS: Overall, 30 (4.2%) GC carried a KRAS mutation. In total, 5.8% of the UK GC, 4% of Japan GC and 1.5% of Singapore GC were KRAS mutant. KRAS mutant GC had fewer lymph node metastases in the UK cohort (P=0.005) and were more frequent in elderly patients in the Japan cohort (P=0.034). KRAS mutations were more frequent in MMR-deficient GC in the UK and the Japanese cohort (P<0.05). A BRAF mutation was only detected in a single Japanese GC. CONCLUSIONS: This large multicentre study demonstrated that KRAS mutations and DNA MMR deficiency have a role in a small subgroup of GC irrespective of country of origin, suggesting that this subgroup of GC may have developed along a common pathway. Further studies need to establish whether concomitant mutations or amplifications of other EGFR signalling pathway genes may contribute to the activation of this pathway in GC.

Comparison of the prognostic value of the 6th and 7th editions of the Union for International Cancer Control TNM staging system in patients with lower esophageal cancer undergoing neoadjuvant chemotherapy followed by surgery.

Carcinoma of the esophagus is classified according to the Union for International Cancer Control (UICC) TNM staging system. The 7th edition of the UICC TNM staging system was published in 2009. This is the first study to compare the prognostic value of the TNM 6th and 7th editions in patients with esophageal carcinoma treated with chemotherapy followed by surgery. Two hundred forty-three patients with esophageal carcinoma were retrospectively selected from two referral centers. All patients received chemotherapy before surgery. Histopathologic data from the resection specimens were retrieved and restaged according to the TNM 7th edition. Disease-specific survival curves were plotted for depth of tumor invasion (ypT), lymph node status (ypN), and ypTNM stage and then compared. Median follow-up after surgery was 2.5 years (range 0.2-9 years). Survival analysis using the log-rank method revealed that there was a significant difference in survival between ypT4 disease and ypT3 disease (P= 0.003), but no difference between ypT0, ypT1, ypT2, and ypT3 categories irrespective of TNM edition used. Survival probability was significantly different between ypN0 and ypN1 (P= 0.001 for TNM 6th and 7th edition), as well as ypN2 and ypN3 (TNM 7th edition, P= 0.004), but not between ypN1 and ypN2 (TNM 7th edition, P= 0.89). Neither the TNM 6th nor 7th edition T staging provides accurate survival probability stratification. However, the advantage of the 7th edition is the introduction of a third tier in survival stratification for patients with nodal involvement.

Artificial intelligence for detection of microsatellite instability in colorectal cancer-a multicentric analysis of a pre-screening tool for clinical application.

BACKGROUND: Microsatellite instability (MSI)/mismatch repair deficiency (dMMR) is a key genetic feature which should be tested in every patient with colorectal cancer (CRC) according to medical guidelines. Artificial intelligence (AI) methods can detect MSI/dMMR directly in routine pathology slides, but the test performance has not been systematically investigated with predefined test thresholds. METHOD: We trained and validated AI-based MSI/dMMR detectors and evaluated predefined performance metrics using nine patient cohorts of 8343 patients across different countries and ethnicities. RESULTS: Classifiers achieved clinical-grade performance, yielding an area under the receiver operating curve (AUROC) of up to 0.96 without using any manual annotations. Subsequently, we show that the AI system can be applied as a rule-out test: by using cohort-specific thresholds, on average 52.73% of tumors in each surgical cohort [total number of MSI/dMMR = 1020, microsatellite stable (MSS)/ proficient mismatch repair (pMMR) = 7323 patients] could be identified as MSS/pMMR with a fixed sensitivity at 95%. In an additional cohort of N = 1530 (MSI/dMMR = 211, MSS/pMMR = 1319) endoscopy biopsy samples, the system achieved an AUROC of 0.89, and the cohort-specific threshold ruled out 44.12% of tumors with a fixed sensitivity at 95%. As a more robust alternative to cohort-specific thresholds, we showed that with a fixed threshold of 0.25 for all the cohorts, we can rule-out 25.51% in surgical specimens and 6.10% in biopsies. INTERPRETATION: When applied in a clinical setting, this means that the AI system can rule out MSI/dMMR in a quarter (with global thresholds) or half of all CRC patients (with local fine-tuning), thereby reducing cost and turnaround time for molecular profiling.

Large negative lymph nodes - a surrogate for immune activation in rectal cancer patients?

AIM: The size of regional, tumor draining lymph nodes without metastasis (LNneg) found in rectal cancer resection specimens varies and seems to be related to patient survival. Yet, the histopathological features influencing LNneg size in rectal cancer have not been studied in detail. Our pilot study focused on investigating the relationship between lymph node (LN) size and LNneg microarchitecture in rectal cancer (RC) resection specimens. METHOD: In this retrospective cohort study, resection specimens from 146 RC patients, treated with either surgery alone (n = 29) or neoadjuvant therapy followed by resection (n = 117), were included in the study. Histology of LNnegs was reviewed to establish number of lymphoid follicles and presence of intranodal fat. Longest long axis and area of each LN were measured digitally. RESULTS: 1830 LNnegs were measured. The microarchitecture was analyzed in a subset of 680 LNnegs. 153 (22.5 %) LNnegs contained intranodal fat. After neoadjuvant treatment, presence of intranodal fat was related to smaller LNneg area (median (range) area of LNneg without intranodal fat: 4.51 mm2 (0.15-46.89 mm2), with intranodal fat: 3.46 mm2 (0.12-27.22 mm2), p = 0.048). A higher number of lymphoid follicles was related to a larger LNneg area in both patient groups (p < 0.001). CONCLUSION: Our pilot data suggest that in rectal cancer the presence of large regional LNnegs may reflect increased immune activation due to tumor related antigens. Further studies are warranted to investigate whether histologically visible microarchitectural features of LNnegs such as lymphoid follicles translate to particular features in radiological images and hence could potentially help to identify LNneg with more certainty at the time of pre-treatment disease staging.

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 (kappa=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.

Molecular pathology--the future?

The diagnosis and management of complex disease requires multidisciplinary clinical collaboration. Histopathological assessment of tissues is an important part of this approach and relies on the morphological appraisal of stained tissues by light microscopy. Although considered the 'gold standard', morphology alone is becoming increasingly insufficient in disease where molecular characterisation has altered clinical practice. As the ability to define the molecular alterations associated with disease expands, the requirement to analyse such alterations for diagnostic and therapeutic purposes follows suit. Despite the widespread use of small scale molecular approaches such as immunohistochemistry and fluorescent in situ hybridisation, the demand for detailed molecular classification of disease states increases unabated. In this review, we summarise the clinical applications of various molecular techniques already used within the modern histopathology department. Thereafter, we consider novel high throughput, array based technologies and their possible impact on future histopathological practice.