Defining a positive circumferential resection margin in oesophageal cancer and its implications for adjuvant treatment

Background

A positive circumferential resection margin (CRM) has been associated with a poorer prognosis in oesophageal and oesophagogastric junctional (OGJ) cancer. The College of American Pathologists defines the CRM as positive if tumour cells are present at the margin, whereas the Royal College of Pathologists also include tumour cells within 1 mm of this margin. The relevance of these differences is not clear and no study has investigated the impact of adjuvant therapy. The aim was to identify the optimal definition of an involved CRM in patients undergoing resection for oesophageal or OGJ cancer, and to determine whether adjuvant radiotherapy improved survival in patients with an involved CRM.

Methods

This was a single-centre retrospective study of patients who had undergone attempted curative resection for a pathological T3 oesophageal or OGJ cancer. Clinicopathological variables and distance from the tumour to the CRM, measured to ± 0.1 mm, were correlated with survival.

Results

A total of 226 patients were included. Sex (P = 0·018), tumour differentiation (P = 0·019), lymph node status (P < 0·001), number of positive nodes (P < 0·001), and CRM distance (P = 0·042) were independently predictive of prognosis. No significant survival difference was observed between positive CRM 0-mm and 0·1–0·9-mm groups after controlling for other prognostic variables. Both groups had poorer survival than matched patients with a CRM at least 1 mm clear of tumour cells. Among patients with a positive CRM of less than 1 mm, those undergoing observation alone had a median survival of 18·6 months, whereas survival was a median of 10 months longer in patients undergoing adjuvant radiotherapy, but otherwise matched for prognostic variables (P = 0·009).

Conclusion

A positive CRM of 1 mm or less should be regarded as involved. Adjuvant radiotherapy confers a significant survival benefit in selected patients with an involved CRM.

Integrative analysis of array-comparative genomic hybridisation and matched gene expression profiling data reveals novel genes with prognostic significance in oesophageal adenocarcinoma

BACKGROUND AND AIMS

The incidence of oesophageal adenocarcinoma (OAC) has been increasing rapidly with a dismal survival rate of less than 20%. Understanding the genomic aberrations and biology of this cancer may enhance disease interventions. This study aimed to use genome-wide genomic and expression data to enhance the understanding of OAC pathogenesis and identify groups with differential outcomes.

METHODS

Array-comparative genomic hybridisation (aCGH) analysis was carried out on 56 fresh frozen OAC resection samples with long-term clinical follow-up data. Samples with aberrations were further analysed with whole-genome single-nucleotide polymorphism arrays to confirm aCGH findings. Matched gene expression microarray data were used to identify genes with high copy number-expression correlations. Nested-multiplex PCR on DNA from microdissected specimens and fluorescence in situ hybridisation assays were used for target validation. Immunohistochemistry on the same cohort and independent samples (n=371) was used for subsequent validation. Kaplan-Meier survival analyses were performed based on aCGH data after unsupervised K-means clustering (K=5, 50 iterations) and immunohistochemistry data.

RESULTS

aCGH identified 17 common regions (>5% samples) of gains and 11 common regions of losses, including novel regions in OAC (loci 11p13 and 21q21.2). Integration of aCGH data with matched gene expression microarray data highlighted genes with high copy number-expression correlations: two deletions (p16/CDKN2A, MBNL1) and four gains (EGFR, WT1, NEIL2, MTMR9). Immunohistochemistry demonstrated protein over-expression of targets with gains: EGFR (10%), WT1 (20%), NEIL2 (14%) and MTMR9 (25%). These targets individually (p<0.060) and in combination had prognostic significance (p=0.008). On the genomic level, K-means clustering identified a cluster (32% of cohort) with differential log(2) ratios of 16 CGH probes (p<4×10(-7)) and a worse prognosis (median survival=1.37 years; p=0.015).

CONCLUSIONS

Integration of aCGH and gene expression data identified copy number aberrations and novel genes with prognostic potential in OAC.

Continual monitoring of intraepithelial lymphocyte immunophenotype and clonality is more important than snapshot analysis in the surveillance of refractory coeliac disease

OBJECTIVE

An aberrant immunophenotype and monoclonality of intraepithelial lymphocytes (IELs) are frequently found in refractory coeliac disease (RCD). However, the utility of continual monitoring of IEL immunophenotype and clonality in the surveillance of RCD remains to be studied.

DESIGN

The diagnostic and follow-up biopsies from 33 patients with CD, 7 with suspected RCD, 41 with RCD and 20 with enteropathy-associated T cell lymphoma (EATL) (including 11 evolved from RCD) were investigated by CD3epsilon/CD8 double immunohistochemistry and PCR-based clonality analysis of the rearranged T cell receptor (TCR) genes.

RESULTS

An aberrant immunophenotype (CD3epsilon(+)CD8(-) IELs > or =40%) and monoclonality were detected occasionally in CD biopsies, either transiently in patients with CD not compliant with a gluten-free diet or in those who subsequently developed suspected RCD, RCD or EATL. In contrast, the aberrant immunophenotype and monoclonality were found in 30 of 41 (73%) and 24 of 37 (65%) biopsies, respectively, at the time of RCD diagnosis. Among the patients with RCD who did not show these abnormalities in their diagnostic biopsies, 8 of 10 (80%) and 5 of 11 (45%) cases gained an aberrant immunophenotype and monoclonality, respectively, during follow-up. Irrespective of whether detected in diagnostic or follow-up biopsies, persistence of both abnormalities was characteristic of RCD. Importantly, the presence of concurrent persistent monoclonality and aberrant immunophenotype, especially > or =80% CD3epsilon(+)CD8(-) IELs, was a strong predictor of EATL development in patients with RCD (p=0.001).

CONCLUSIONS

Continual monitoring of both immunophenotype and clonality of IELs is more important than snapshot analysis for RCD diagnosis and follow-up, and could provide a useful tool for surveillance of patients at risk of EATL.

Mechanisms and sequelae of E-cadherin silencing in hereditary diffuse gastric cancer

Around 25-40% of cases of hereditary diffuse gastric cancer (HDGC) are caused by heterozygous E-cadherin (CDH1) germline mutations. The mechanisms for loss of the second allele still remain unclear. The aims of this study were to elucidate mechanisms for somatic inactivation of the wild-type CDH1 allele and to seek evidence for cadherin switching. Archival tumour material was analysed from 16 patients with CDH1 germline mutations and seven patients fulfilling HDGC criteria without CDH1 germline mutations. The 16 CDH1 exons were sequenced. E-cadherin promoter methylation was analysed by bisulphite sequencing and pyrosequencing and allele specificity was determined using polymorphic loci. Loss of heterozygosity was analysed using microsatellite markers. Cadherin expression levels were determined by real-time RT-PCR and immunohistochemistry. Six of 16 individuals with germline mutations had at least one second hit mechanism. Two exonic mutations (exon 9 truncating, exon 3 missense) and four intronic mutations which may affect splicing were identified. Tumours from 4/16 individuals had promoter hypermethylation that was restricted to the A allele haplotype in three cases. E-cadherin loss (mRNA and protein) generally correlated with identification of a second hit. In cases without germline E-cadherin mutations there was no evidence for somatic mutation or significant promoter methylation. P-cadherin (>25% cells) was expressed in 7/13 (54%) and 4/5 (80%) with and without germline CDH1 mutations, respectively, independent of complete E-cadherin loss. Overall, inactivation of the second CDH1 allele occurs by mutation and methylation events. Methylation is commonly allele-specific and is uncommon without germline mutations. P-cadherin over-expression commonly occurs in individuals with diffuse type gastric cancer.

Histopathological and molecular analysis of gastrectomy specimens from hereditary diffuse gastric cancer patients has implications for endoscopic surveillance of individuals at risk

Hereditary diffuse gastric cancer (HDGC) is caused by germline E-cadherin (CDH1) mutations in 25-40% of tested families. Management options for asymptomatic mutation carriers are fraught, since endoscopic surveillance can miss cancer foci and prophylactic gastrectomy has profound clinical sequelae. The aims of this study were to evaluate the impact of current surveillance practices on pre-operative diagnosis and to characterize the microscopic lesions in gastrectomy specimens to better inform clinical practice. Histological assessment and mapping of endoscopic surveillance and gastrectomy specimens were performed for eight asymptomatic CDH1 mutation carriers. E-cadherin expression and proliferation were analysed and evidence of epithelial-mesenchymal transition (EMT) was sought by immunohistochemistry for vimentin and cytokeratin 8/18. Four of eight patients had lesions detected at endoscopic surveillance. A median of 20.5 (range 0-66) signet ring foci were identified per gastrectomy (including in situ lesions and pagetoid spread). Foci were predominantly identified in the fundus and body (90% endoscopic biopsies and 85% in gastrectomy). The likelihood of detecting foci pre-operatively was positively correlated with the number of biopsies taken and the number of lesions in the gastrectomy specimen. E-cadherin expression in gastrectomy specimens was reduced or absent in all of the foci compared with the intervening gastric tissue, suggesting that these lesions are polyclonal. The foci had a low proliferative index (<2%) and there was no evidence for EMT. Multiple endoscopic biopsy sampling of the gastric mucosa increases the yield of microscopic cancer foci. The low proliferative index and lack of EMT suggests that these foci may represent an indolent stage of HDGC.

RECIST and Choi criteria for response assessment (RA) in patients with inoperable and metastatic gastrointestinal stromal tumours (GISTs) on imatinib mesylate. Cambridge GIST study group experience

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Background: Imatinib Mesylate (IM) induces an overall response rate of 84% in patients (pts) with metastatic GISTs. Standard RA is by RECIST criteria. This may underestimate the true benefit of IM in such pts. Choi et al observed ↓ in size (10%) and or density (D) (15%) correlated well with disease specific survival. We report our experience using both RECIST and Choi criteria for RA in GIST pts on IM. Methods: Between 2003 and 06, 24 pts with metastatic or inoperable GISTs were treated with IM. 50 lesions (Liver 20, Omentum 21, Primary 9) were identified at presentation on contrast CT (Siemens multi slice CT, IV Niopam, GE PACS system). 3 monthly CT was used for RA until tumour progression (PD) or death. Parameters recorded were: 1.Largest dimension 2. Lesion density (Mean Hounsfield units, HFU) 3.New lesions 4.Any new features. RECIST and Choi criteria were both applied for RA. Results: N=50. At 3 months (m) only 16% of the lesions achieved partial response (PR) by RECIST and 24% increased in size by a mean of 22.5% (Range 3–150%). RA as measured by Choi criteria revealed 88% of lesions had either a 10% ↓ in size or a 15% ↓ in D at 3 m. Mean ↓ in D was 29% (95% CI 24.6–33.4). At 18 m 50% of the lesions achieved PR and 20% had PD by RECIST criteria, and with Choi criteria 68% RR was recorded. Calcification, haemorrhage and perforation within the lesions spuriously altered the mean D value in 15% of the lesions which made assessment by Choi criteria difficult. In 5 pts new hepatic cystic lesions (range 2–22) appeared with a mean D of 16 HF. None were detected in extra-hepatic sites. 4 pts showed new calcifications within lesions 3–18 m on IM. Enhancing nodules within lesions were seen in 4 pts predating clinical PD by 6–18 m. Conclusions: Choi criteria were found to be reproducible in our pts. RRs at 3 months using Choi criteria (88%) were far greater than by RECIST criteria (16%). RRs were more similar at 18 m (68% Choi vs 50% RECIST).Using density for RA can become unreliable in the presence of perforation, calcification and haemorrhage. These criteria should be evaluated by a radiologist experienced in assessing the response to IM in GISTs with awareness of their limitations.

No significant financial relationships to disclose.

Plasma and dietary carotenoid, retinol and tocopherol levels and the risk of gastric adenocarcinomas in the European prospective investigation into cancer and nutrition

Despite declining incidence rates, gastric cancer (GC) is a major cause of death worldwide. Its aetiology may involve dietary antioxidant micronutrients such as carotenoids and tocopherols. The objective of this study was to determine the association of plasma levels of seven common carotenoids, their total plasma concentration, retinol and α- and γ-tocopherol, with the risk of gastric adenocarcinoma in a case–control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC), a large cohort involving 10 countries. A secondary objective was to determine the association of total sum of carotenoids, retinol and α-tocopherol on GCs by anatomical subsite (cardia/noncardia) and histological subtype (diffuse/intestinal). Analytes were measured by high-performance liquid chromatography in prediagnostic plasma from 244 GC cases and 645 controls matched by age, gender, study centre and date of blood donation. Conditional logistic regression models adjusted by body mass index, total energy intake, smoking and Helicobacter pylori infection status were used to estimate relative cancer risks. After an average 3.2 years of follow-up, a negative association with GC risk was observed in the highest vs the lowest quartiles of plasma β-cryptoxanthin (odds ratio (OR)=0.53, 95% confidence intervals (CI)=0.30–0.94, P_trend=0.006), zeaxanthin (OR=0.39, 95% CI=0.22–0.69, P_trend=0.005), retinol (OR=0.55, 95% CI=0.33–0.93, P_trend=0.005) and lipid-unadjusted α-tocopherol (OR=0.59, 95% CI=0.37–0.94, P_trend=0.022). For all analytes, no heterogeneity of risk estimates or significant associations were observed by anatomical subsite. In the diffuse histological subtype, an inverse association was observed with the highest vs lowest quartile of lipid-unadjusted α-tocopherol (OR=0.26, 95% CI=0.11–0.65, P_trend=0.003). These results show that higher plasma concentrations of some carotenoids, retinol and α-tocopherol are associated with reduced risk of GC.

Hepatocellular carcinoma tumour thrombus in a re-canalised para-umbilical vein: detection by 18-fluoro-2-deoxyglucose positron emission tomography imaging

This case report describes an unusual site of tumour thrombus in a re-canalised para-umbilical vein, in a patient with hepatocellular carcinoma (HCC) and cirrhosis. The tumour thrombus was suspected on conventional radiography and confirmed using PET imaging, illustrating the complimentary value of structural and functional imaging in achieving the correct diagnosis.

An immunochemical analysis of mdm2 expression in human breast cancer and the identification of a growth-regulated cross-reacting species p170

mdm2 is a 491 amino acid nuclear protein which is involved in complex interactions with important cell-cycle and stress-response regulators including p53, Rb and E2F. Recent data implicate mdm2 in the regulation of both p53 activity and level, and burgeoning data suggest that mdm2 may be involved in human epithelial tumourigenesis, including breast cancer. In this study the expression of mdm2 protein has been investigated in a series of 54 human breast carcinomas using immunoblotting methods. Overexpression of the predominant p90 mdm2 isoform is common in breast cancer (54 per cent) and this is not frequently a consequence of gene amplification. There is no relationship between p90 expression and either p53 protein expression or p53 mutational status. Additional mdm2 immunoreactive species of differing mobilities are identifiable, greatly complicating the analysis. For example, a p170 form is seen in many breast cancer samples (44 per cent) using 2A10 but is not identified by 3G5. This 2A10 immunoreactive species, which is almost certainly not an mdm2 isoform, is a growth-regulated protein, being undetectable in resting peripheral blood lymphocytes and rising to high levels after PHA stimulation. In contrast to mdm2 (p90), p170 is not induced by DNA damage caused by UV light. p170 is identifiable in mdm2 null cells by immunoblotting and is detected as a nuclear protein. While mdm2 immunostaining studies are increasing, this report highlights the complexity of mdm2 analysis in vivo and emphasizes the need to correlate immunohistological and biochemical assays since, in some mdm2 (p90) negative tumours, nuclear immunoreactivity may be identified as a consequence of cross-reacting species such as p170.

Why is p53 protein stabilized in neoplasia? Some answers but many more questions?

The p53 pathway provides a physiological system for integrating signals from diverse insults and eliciting adaptive cellular responses that include (but importantly are not restricted to) growth arrest and apoptosis. Defects in the pathway are prevalent in cancer, most notably being associated with mis-sense mutations in p53 itself. This leads to the inability of p53 to act as a transcription factor and thus to the non-occurrence of downstream events. Recent data indicate that the stability (and hence level) of p53 protein in cells is regulated by its interaction with mdm2: this results in enhanced p53 degradation by ubiquitin-mediated events. Since mdm2 is itself regulated by p53, loss of function of p53 leads to lack of mdm2 and thus to p53 protein accumulation. This provides a mechanistic explanation for the observation that p53 accumulation is associated with neoplasia. It may be that accumulation of p53 in the absence of p53 mutation can occur as a consequence of mdm2 defects, as well as being a physiological response in many situations. Another recent development is the recognition of p53 homologues (p73 alpha, p73 beta, and KET) which have many sequence and probable structural features in common with p53. It seems likely that this will reveal another layer of complexity in the control and regulation of p53 and its role in physiology and pathology.

APC expression in normal human tissues

The tumour suppressor gene APC codes for a 2843-amino acid protein whose precise functions are still poorly understood. This paper describes the development of two new antisera to APC (to amino- and carboxy-terminal epitopes) which permit localization of the protein by immunohistochemistry in archival paraffin sections. The protein is expressed in a wide variety of normal epithelial tissues. Its distribution frequently coincides with the location of post-replicative cells within tissues. Staining patterns demonstrate that the APC protein, although often diffusely cytoplasmic in distribution, may also accumulate in the apical and immediately subapical regions, or along the lateral margins of certain cells. These results indicate that APC is significant in many tissues in addition to the colorectal epithelium. They are compatible with a function related to signalling at the adherens junction and possibly with other more complex roles in cells committed to terminal differentiation.

APC expression in normal human tissues

The tumour suppressor gene APC codes for a 2843-amino acid protein whose precise functions are still poorly understood. This paper describes the development of two new antisera to APC (to amino- and carboxy-terminal epitopes) which permit localization of the protein by immunohistochemistry in archival paraffin sections. The protein is expressed in a wide variety of normal epithelial tissues. Its distribution frequently coincides with the location of post-replicative cells within tissues. Staining patterns demonstrate that the APC protein, although often diffusely cytoplasmic in distribution, may also accumulate in the apical and immediately subapical regions, or along the lateral margins of certain cells. These results indicate that APC is significant in many tissues in addition to the colorectal epithelium. They are compatible with a function related to signalling at the adherens junction and possibly with other more complex roles in cells committed to terminal differentiation.

Demonstration of DNA damage/repair in individual cells using in situ end labelling: association of p53 with sites of DNA damage

We describe the development and application of in situ end labelling (ISEL) to identity sites of damaged DNA in the nuclei of individual cells. In cell culture, exposure to a variety of genotoxic agents induced a dose and time-dependent increase in nuclear labelling. In addition, examination of histological sections of human skin exposed to solar-stimulated UV light showed ISEL in both keratinocytes and superficial dermal cells, with the same spatial and temporal distribution as that of a marker of DNA repair, PCNA (proliferating cell nuclear antigen). Using co-localization techniques and confocal microscopy, we found increased levels of p53 in many ISEL-positive cells in vitro, with a similar distribution of labelling in the nucleus. This observation provides further evidence for a direct role of p53 in the recognition of damaged DNA. Thus, ISEL should prove a convenient method for demonstrating genotoxic insult in individual cells and in histological material, and may have value in toxicological screening. This high-resolution microscopy technique can also be used to compare the spatial distribution of various proteins implicated in the response to DNA damage with the sites of the lesion.