Jeremy Parfitt

Increasing incidence of adenocarcinoma of the gastroesophageal junction and distal stomach in Canada – An epidemiological study from 1964 to 2002

BACKGROUND The increasing incidence of esophageal and proximal gastric (cardia) adenocarcinoma and the decreasing incidence of distal gastric (antropyloric) adenocarcinoma has been documented in several populations. The aim of the present study was to examine incidence trends of these neoplasms in Ontario, Canadas most populous province, over a 39-year period. METHODS Analyses were based on data obtained from the Ontario Cancer Registry of Cancer Care Ontario. Number of cases and rates per 100,000 age-adjusted to the 1996 Canadian standard, were obtained for all esophageal and gastric carcinoma cases reported between 1964 and 2002. Rates were grouped into five-year periods to analyze trends over the 39-year period. Point and 95% CI estimates of average annual percentage change in incidence rates were calculated with a log-linear regression model. RESULTS The incidence of adenocarcinoma of the distal esophagus increased in men and women (average annual increase of 9.5% in men; 4.3% in women). The incidence of adenocarcinoma of the cardia increased in men and women (average annual increase of 7.3% in men; 5.8% in women). The incidence of antropyloric adenocarcinoma increased in men and women (average annual increase of 4.4% in men; 5.3% in women). The incidence of esophageal squamous cell carcinoma remained stable. CONCLUSIONS There has been a significant increase in the incidence of adenocarcinoma around the gastroesophageal junction in men over the 39-year study period. The increase in incidence of distal gastric adenocarcinoma is unexpected and may relate to a reclassification phenomenon, immigration trends in Ontario and a rising incidence of diffuse/signet ring cell adenocarcinoma.

Re-Directing an Alkylating Agent to Mitochondria Alters Drug Target and Cell Death Mechanism

We have successfully delivered a reactive alkylating agent, chlorambucil (Cbl), to the mitochondria of mammalian cells. Here, we characterize the mechanism of cell death for mitochondria-targeted chlorambucil (mt-Cbl) in vitro and assess its efficacy in a xenograft mouse model of leukemia. Using a ρ° cell model, we show that mt-Cbl toxicity is not dependent on mitochondrial DNA damage. We also illustrate that re-targeting Cbl to mitochondria results in a shift in the cell death mechanism from apoptosis to necrosis, and that this behavior is a general feature of mitochondria-targeted Cbl. Despite the change in cell death mechanisms, we show that mt-Cbl is still effective in vivo and has an improved pharmacokinetic profile compared to the parent drug. These findings illustrate that mitochondrial rerouting changes the site of action of Cbl and also alters the cell death mechanism drastically without compromising in vivo efficacy. Thus, mitochondrial delivery allows the exploitation of Cbl as a promiscuous mitochondrial protein inhibitor with promising therapeutic potential.

A comparison of survival and pathologic features of non-alcoholic steatohepatitis and hepatitis C virus patients with hepatocellular carcinoma.

AIM To compare the clinical outcome and pathologic features of non-alcoholic steatohepatitis (NASH) patients with hepatocellular carcinoma (HCC) and hepatitic C virus (HCV) patients with HCC (another group in which HCC is commonly seen) undergoing liver transplantation. METHODS Patients transplanted for HCV and NASH at our institution from January 2000 to April 2011 were analyzed. All explanted liver histology and pre-transplant liver biopsies were examined by two specialist liver histopathologists. Patient demographics, disease free survival, explant liver characteristics and HCC features (tumour number, cumulative tumour size, vascular invasion and differentiation) were compared between HCV and NASH liver transplant recipients. RESULTS A total of 102 patients with NASH and 283 patients with HCV were transplanted. The incidence of HCC in NASH transplant recipients was 16.7% (17/102). The incidence of HCC in HCV transplant recipients was 22.6% (64/283). Patients with NASH-HCC were statistically older than HCV-HCC patients (P < 0.001). A significantly higher proportion of HCV-HCC patients had vascular invasion (23.4% vs 6.4%, P = 0.002) and poorly differentiated HCC (4.7% vs 0%, P < 0.001) compared to the NASH-HCC group. A trend of poorer recurrence free survival at 5 years was seen in HCV-HCC patients compared to NASH-HCC who underwent a Liver transplantation (P = 0.11). CONCLUSION Patients transplanted for NASH-HCC appear to have less aggressive tumour features compared to those with HCV-HCC, which likely in part accounts for their improved recurrence free survival.

Reduction of Liver Ischemia Reperfusion Injury by Silencing of TNF-α Gene with shRNA

BACKGROUND Tumor necrosis factor-alpha (TNF-α) is a central mediator in the hepatic response to ischemia/reperfusion. Short hairpin RNA (shRNA) has been proven to be an effective means of harnessing the RNA interference pathway in mammalian cells. In the current study, we investigated whether silencing TNF-α gene with shRNA can prevent liver ischemic reperfusion injury (IRI). METHODS Male BalB/c mice were randomized to TNF-α shRNA, scramble shRNA, or sham operation groups. TNF-α shRNA and scramble shRNA groups were injected 48 h before inducing IRI. IRI was induced via microaneurysm clamps applied to the left hepatic artery and portal vein. Six hours after reperfusion, IRI injury was examined by serum level of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), liver histopathology, MPO, and MDA level, as well as by relative quantities of TNF-α mRNA. RESULTS TNF-α expression induced by ischemia reperfusion in the liver was significantly suppressed after treatment with TNF-α shRNA compared with the group treated with scramble shRNA (P < 0.001). Mice treated with TNF-α shRNA showed lower peak values of AST and ALT than scramble shRNA treated mice (P < 0.001). On histopathologic slides, mice treated with TNF-α shRNA had significantly less ischemia/reperfusion injury based on Suzuki score than the scramble shRNA group, 3.57 ± 2.30 and 8.83 ± 0.98 respectively (P < 0.001), while the sham group was not significantly different from the TNF-alpha shRNA group, 0 ± 0 and 3.57 ± 2.30, respectively (P = 0.075). Liver tissue MDA levels were significantly lower in mice treated with TNF-α shRNA as compared with the group treated with scramble shRNA (P < 0.01). Immunohistochemical staining for MPO was significantly lower in mice treated with TNF-α shRNA compared with the group treated with shRNA (compared with treated with scramble shRNA group.) CONCLUSIONS Liver IRI can be minimized through gene silencing of TNF-α. This may represent a novel therapy in the setting of transplantation and in other conditions associated with IRI of the liver.

Metastatic PEComa to the brain

Neoplasms of perivascular epithelioid cells (PEComas) have in common the co-expression of melanocytic and muscle immunohistochemical markers. While most reported PEComas have behaved in a benign fashion, malignant PEComas have occasionally been documented [3–5]. We present a case of malignant PEComa, which was Wrst diagnosed as a brain metastasis; this represents the Wrst documentation of brain involvement by PEComa. A 53-year-old woman presented with malaise. Computerized tomography (CT) of the chest and abdomen revealed multiple lung lesions bilaterally, as well as a solitary mass in the left adrenal gland. The largest lung lesion was located in the right upper lobe and measured 5.4 £ 3.5 £ 3.4 cm, while the adrenal mass measured 4.8 £ 3.2 £ 2.9 cm. Fine needle aspiration of one of the lung lesions was interpreted as indeterminate for malignancy. The liver, pancreas, spleen and kidneys were normal by abdominal imaging. Several months later, she presented with headache, nausea and vomiting. She had diYculty with naming. A CT scan of her head revealed a mass in the left posterior temporal lobe, which was mostly solid with cystic components (Fig. 1). The patient underwent a temporal craniotomy and resection of the brain tumor. Postoperatively, neuroimaging showed no evidence of residual tumor. The patient’s headache improved and she was discharged home. Pathologic examination of resected tumor tissue showed cells arranged in sheets and nests, invested with a prominent capillary vasculature (Fig. 2a). The interface between tumor and uninvolved brain was sharp and several foci of necrosis were present. The neoplastic cells were epithelioid, with abundant cytoplasm that varied from eosinophilic and granular to clear (Fig. 2b). The nuclei were round with moderate pleomorphism and they often contained conspicuous nucleoli; mitoses were rare. Periodic acid–SchiV (PAS) staining, with and without diastase digestion, demonstrated intracytoplasmic glycogen (Fig. 2c). The biopsied lung lesion was morphologically similar to the brain tumor, although there was greater nuclear pleomorphism and more prominent nucleoli in the latter. Immunohistochemistry showed strong positivity within tumor cells for HMB45, Melan-A and caldesmon, while desmin was focally positive (Fig. 3a, b). The neoplastic cells failed to stain with antibodies against S100, tyrosinase, epithelial membrane antigen (EMA), vimentin, cytokeratin (AE1/AE3, 8/18, 7/20, 34BE12), inhibin, actin (smooth muscle and muscle speciWc), smooth muscle myosin, neuron speciWc enolase (NSE), synaptophysin, chromogranin, neuroWlament, glial Wbrillary acidic protein (GFAP), CD10, CD99, CD117, CD34, carcinoma embryonic antigen (mono and polyclonal), calretinin, heppar1 and placental alkaline phosphatase. Ultrastructural examination of glutaraldehyde-Wxed tissue revealed intracytoplasmic glycogen and lipid. Premelanosomes and desmosomes were absent. The WHO has recently oVered formal recognition to a group of neoplasms with perivascular epithelioid cell diVerentiation. This group of tumors have in common the presence of epithelioid to spindle cells with J. R. ParWtt (&) · J. L. Keith · J. F. Megyesi · L. C. Ang Department of Pathology, London Health Sciences Centre, University of Western Ontario, 339 Windermere Road, London, ON, Canada N6A 5A5, e-mail: jrparWt@uwo.ca

Interobserver variability in assessing dysplasia and architecture in colorectal adenomas: a multicentre Canadian study

Aims Following the introduction of colorectal cancer screening programmes throughout Canada, it became necessary to standardise the diagnosis of colorectal adenomas. Canadian guidelines for standardised reporting of adenomas were developed in 2011. The aims of the present study were (a) to assess interobserver variability in the classification of dysplasia and architecture in adenomas and (b) to determine if interobserver variability could be improved by the adoption of criteria specified in the national guidelines. Methods An a priori power analysis was used to determine an adequate number of cases and participants. Twelve pathologists independently classified 40 whole-slide images of adenomas according to architecture and dysplasia grade. Following a wash-out period, participants were provided with the national guidelines and asked to reclassify the study set. Results At baseline, there was moderate interobserver agreement for architecture (K=0.4700; 95% CI 0.4427 to 0.4972) and dysplasia grade (K=0.5680; 95% CI 0.5299 to 0.6062). Following distribution of the guidelines, there was improved interobserver agreement in assessing architecture (K=0.5403; 95% CI 0.5133 to 0.5674)). For dysplasia grade, overall interobserver agreement remained moderate but decreased significantly (K=0.4833; 95% CI 0.4452 to 0.5215). Half of the cases contained high-grade dysplasia (HGD). Two pathologists diagnosed HGD in ≥75% of cases. Conclusions The improvement in interobserver agreement in classifying adenoma architecture suggests that national guidelines can be useful in disseminating knowledge, however, the variability in the diagnosis of HGD, even following guideline review suggests the need for ongoing knowledge-transfer exercises.

The Future Liver Remnant in Patients Undergoing the Associating Liver Partition with Portal Vein Ligation for Staged Hepatectomy (ALPPS) Maintains the Immunological Components of a Healthy Organ.

Background and Aims A short-interval, two-stage approach termed associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) increases the number of patients with extensive malignant disease of the liver and a small future liver remnant (FLR) that can undergo liver resection. While this approach results in accelerated liver hypertrophy of the FLR, it remains unknown whether this phenomenon is restricted to liver parenchymal cells. In the current study, we evaluated whether ALPPS alters the immunological composition of the deportalized lobe (DL) and the FLR. Methods In this prospective, single-center study, liver tissue from the DL and the FLR were collected intra-operatively from adult patients undergoing ALPPS for their liver metastases. The extent of hypertrophy of the FLR was determined by volumetric helical computed tomography. Flow cytometry and histological analyses were conducted on liver tissues to compare the frequency of several immune cell subsets, and the architecture of the liver parenchyma between both stages of ALPPS. Results A total of 12 patients completed the study. Histologically, we observed a patchy peri-portal infiltration of lymphocytes within the DL, and a significant widening of the liver cords within the FLR. Within the DL, there was a significantly higher proportion of B cells and CD4+ T cells as well innate-like lymphocytes, namely mucosa-associated invariant T (MAIT) cells and natural killer T (NKT) cells following ALPPS. In contrast, the frequency of all evaluated immune cell types remained relatively constant in the FLR. Conclusion Our results provide the first description of the immunological composition of the human liver following ALPPS. We show that following the ALPPS procedure, while the immune composition of the FLR remains relatively unchanged, there is a moderate increase in several immune cell populations in DL. Overall, our results support the continued utilization of the ALPPS procedure.