Selliah Kanthan

Molecular events in primary and metastatic colorectal carcinoma: a review.

Colorectal cancer (CRC) is a heterogeneous disease, developing through a multipathway sequence of events guided by clonal selections. Pathways included in the development of CRC may be broadly categorized into (a) genomic instability, including chromosomal instability (CIN), microsatellite instability (MSI), and CpG island methylator phenotype (CIMP), (b) genomic mutations including suppression of tumour suppressor genes and activation of tumour oncogenes, (c) microRNA, and (d) epigenetic changes. As cancer becomes more advanced, invasion and metastases are facilitated through the epithelial-mesenchymal transition (EMT), with additional genetic alterations. Despite ongoing identification of genetic and epigenetic markers and the understanding of alternative pathways involved in the development and progression of this disease, CRC remains the second highest cause of malignancy-related mortality in Canada. The molecular events that underlie the tumorigenesis of primary and metastatic colorectal carcinoma are detailed in this manuscript.

Gallbladder Cancer in the 21st Century

Gallbladder cancer (GBC) is an uncommon disease in the majority of the world despite being the most common and aggressive malignancy of the biliary tree. Early diagnosis is essential for improved prognosis; however, indolent and nonspecific clinical presentations with a paucity of pathognomonic/predictive radiological features often preclude accurate identification of GBC at an early stage. As such, GBC remains a highly lethal disease, with only 10% of all patients presenting at a stage amenable to surgical resection. Among this select population, continued improvements in survival during the 21st century are attributable to aggressive radical surgery with improved surgical techniques. This paper reviews the current available literature of the 21st century on PubMed and Medline to provide a detailed summary of the epidemiology and risk factors, pathogenesis, clinical presentation, radiology, pathology, management, and prognosis of GBC.

High Expression of Methionine Aminopeptidase 2 in Human Colorectal Adenocarcinomas

Purpose: Several viral and eukaryotic proteins required for signal transduction and regulatory functions undergo lipophilic modification by the enzyme N-myristoyltransferase. Previously we reported that N-myristoyltransferase activity is higher in colon and gallbladder carcinoma than in the corresponding normal tissues. Methionine aminopeptidase 2 (MetAP2) is a bifunctional protein that plays a critical role in the regulation of post-translational processing and protein synthesis. To investigate whether MetAP2 contributes to the pathogenesis of colon carcinoma, we investigated the expression of MetAP2 in both normal and invasive tumor components of human samples. Experimental Design: We evaluated 50 cases of colon carcinoma for this study. In this report we analyzed 15 cases for MetAP2 activity and 13 cases for the expression of MetAP2 by Western blot in both the normal and in invasive tumor components of human samples. In addition, immunohistochemistry analysis was also carried out on samples from all patients. Results: MetAP activity was elevated in all cancerous tissues compared with normal tissues. Western blot analysis also showed the higher expression of MetAP2 in all cases of cancerous tissues. In addition, immunohistochemistry analysis revealed that all cases of colorectal adenocarcinoma showed moderate to strong cytoplasmic positivity for MetAP2 with increased intensity in the invasive component. Conclusions: Elevated MetAP protein expression is associated with metastatic tumor progression and appears to be a strong molecular marker for clinical prognosis. MetAP2 inhibition may represent a potential target for therapeutic intervention in colorectal carcinoma.

Should noncurative resection of the primary tumour be performed in patients with stage IV colorectal cancer? A systematic review and meta-analysis

PURPOSE Surgical resection of the primary tumour in patients with advanced colorectal cancer (crc) remains controversial. This review compares survival in patients with advanced crc who underwent surgical resection of the primary tumour with that in patients not undergoing resection, and determines rates of post-operative mortality and nonfatal complications, the primary tumour complication rate, the non-resection surgical procedures rate, and quality of life (qol). METHODS Reports in the central, medline, and embase databases were searched for relevant studies, which were selected using pre-specified eligibility criteria. The search was also restricted to publication dates from 1980 onward, the English language, and studies involving human subjects. Screening, evaluation of relevant articles, and data abstraction were performed in duplicate, and agreement between the abstractors was assessed. Articles that met the inclusion criteria were assessed for quality using the Newcastle-Ottawa Scale. Data were collected and synthesized per protocol. RESULTS From among the 3379 reports located, fifteen retrospective observational studies were selected. Of the 12,416 patients in the selected studies, 8620 (69%) underwent surgery. Median survival was 15.2 months (range: 10-30.7 months) in the resection group and 11.4 months (range: 3-22 months) in the non-resection group. Hazard ratio for survival was 0.69 [95% confidence interval (ci): 0.61 to 0.79] favouring surgical resection. Mean rates of postoperative mortality and nonfatal complications were 4.9% (95% ci: 0% to 9.7%) and 25.9% (95%ci: 20.1% to 31.6%) respectively. The mean primary tumour complication rate was 29.7% (95% ci: 18.5% to 41.0%), and the non-resection surgical procedures rate in the non-resection group was 27.6% (95 ci: 15.4% to 39.9%). No study provided qol data. CONCLUSIONS Although this review supports primary tumour resection in advanced crc, the results have significant biases. Randomized trials are warranted to confirm the findings.

Gastric biomarkers: a global review

BackgroundGastric cancer is an aggressive disease with a poor 5-year survival and large global burden of disease. The disease is biologically and genetically heterogeneous with a poorly understood carcinogenesis at the molecular level. Despite the many prognostic, predictive, and therapeutic biomarkers investigated to date, gastric cancer continues to be detected at an advanced stage with resultant poor clinical outcomes.Main bodyThis is a global review of gastric biomarkers with an emphasis on HER2, E-cadherin, fibroblast growth factor receptor, mammalian target of rapamycin, and hepatocyte growth factor receptor as well as sections on microRNAs, long noncoding RNAs, matrix metalloproteinases, PD-L1, TP53, and microsatellite instability.ConclusionA deeper understanding of the pathogenesis and biological features of gastric cancer, including the identification and characterization of diagnostic, prognostic, predictive, and therapeutic biomarkers, hopefully will provide improved clinical outcomes.

Fecal molecular markers for colorectal cancer screening.

Despite multiple screening techniques, including colonoscopy, flexible sigmoidoscopy, radiological imaging, and fecal occult blood testing, colorectal cancer remains a leading cause of death. As these techniques improve, their sensitivity to detect malignant lesions is increasing; however, detection of precursor lesions remains problematic and has generated a lack of general acceptance for their widespread usage. Early detection by an accurate, noninvasive, cost-effective, simple-to-use screening technique is central to decreasing the incidence and mortality of this disease. Recent advances in the development of molecular markers in faecal specimens are encouraging for its use as a screening tool. Genetic mutations and epigenetic alterations that result from the carcinogenetic process can be detected by coprocytobiology in the colonocytes exfoliated from the lesion into the fecal matter. These markers have shown promising sensitivity and specificity in the detection of both malignant and premalignant lesions and are gaining popularity as a noninvasive technique that is representative of the entire colon. In this paper, we summarize the genetic and epigenetic fecal molecular markers that have been identified as potential targets in the screening of colorectal cancer.

Three uncommon adrenal incidentalomas: a 13-year surgical pathology review

BackgroundThe discovery of adrenal incidentalomas due to the widespread use of sophisticated abdominal imaging techniques has resulted in an increasing trend of adrenal gland specimens being received in the pathology laboratory. In this context, we encountered three uncommon adrenal incidentalomas.The aim of this manuscript is to report in detail the three index cases of adrenal incidentalomas in the context of a 13-year retrospective surgical pathology review.MethodsThe three index cases were investigated and analyzed in detail with relevant review of the English literature as available in PubMed and Medline. A 13-year retrospective computer-based histopathological surgical review was conducted in our laboratory and the results were analyzed in the context of evidence-based literature on adrenal incidentalomas.ResultsA total of 94 adrenal specimens from incidentalomas were identified, accounting for 0.025% of all surgical pathology cases. In all 76.6% were benign and 23.4% were malignant. A total of 53 females (56.4%) and 41 males (43.6%) aged 4 to 85 years were identified. The benign lesions included cortical adenoma (43.1%), pheochromocytoma (29.3%) and inflammation/fibrosis/hemorrhage (8.3%). Metastatic neoplasms were the most common malignant lesions (50%) followed by primary adrenocortical carcinomas (31.8%) and neuroblastoma (13.6%). These cases were discovered as adrenal incidentalomas that led to surgical exploration.The three index cases of adrenal incidentalomas with unusual pathologies were encountered that included (a) adrenal ganglioneuroma, (b) periadrenal schwannoma and (c) primary adrenal pleomorphic leiomyosarcoma. These cases are discussed, with a literature and clinicopathological review.ConclusionsAdrenal lesions are uncommon surgical specimens in the pathology laboratory. However, higher detection rates of adrenal incidentalomas aided by the ease of laparoscopic adrenalectomy has resulted in increased adrenal surgical specimens leading to unsuspected diagnostic and management dilemmas. Accurate pathological identification of common and uncommon adrenal incidentalomas is essential for optimal patient management.

Increased expression of calcineurin in human colorectal adenocarcinomas

Colorectal cancer (CRC) is the third most common cause of cancer death in the Western world. Calcineurin (CaN), a Ca2+/calmodulin (CaM)‐dependent protein phosphatase, is important for Ca2+‐mediated signal transduction. The main objective of this study is to examine the potential role of Ca2+/CaM‐dependent protein phosphatase in both normal and in invasive tumor components of human samples. In this study, we carried out 45 cases of CaN activity, 13 cases of CaN protein expression by Western blot analysis, and 6 cases for immunohistochemical analysis in both normal and invasive tumor components of human samples. Immunohistochemical analysis revealed that strong cytoplasmic staining of varying intensity was observed in colon tumors of all patients compared to normal mucosa. In addition, Western blot analysis revealed a prominent overexpressed immunoreactive band with an apparent molecular mass of 60 kDa catalytic alpha subunit (CaN A) as well as CaN Aα and β in colon tumor samples. Elevated CaN protein expression appears to be a possible link between Ca2+ signaling and oncogenic processes.

Colonic carcinoid metastatic to the breast.

Metastatic tumors of the breast are uncommon. Breast metastases from nonmammary malignant neoplasms are rare, accounting for approximately 2% of all breast tumors. We report the case of an ileal carcinoid tumor metastatic to the breast 10 years after the initial diagnosis. A 53-year-old woman presented to our clinic with a palpable breast lump. The mammogram was nonspecific. A lumpectomy was performed that, on frozen section, showed a neoplastic lesion. Permanent sections showed that the tumor was composed of sheets of small uniform cells divided into lobules by delicate vascular septa. Immunohistochemical analysis showed that the lesional cells were strongly positive to the neuroendocrine marker panel of antibodies: chromogranin A, neuron-specific enolase, synaptophysin, serotonin, and low-molecular-weight keratin. The lesional cells were negative to cytokeratins 7 and 20, estrogen and progesterone receptors, carcinoembryonic antigen, and c-Erb-B2 antibodies. The presence of pleomorphic neurosecretory-type granules within the cytoplasm of the tumor cells by ultrastructural analysis strongly suggested a metastatic lesion from a midgut carcinoid. A detailed review of the patients medical records confirmed a right hemicolectomy for an ileal carcinoid with lymph node and omental metastases that had been performed elsewhere 10 years earlier. A detailed pathologic analysis of this lesion by light microscopy, along with histochemical, immunohistochemical, and ultrastructural analyses, aided in confirming the metastatic nature of the current breast lesion.

Unusual Retrorectal Lesion

Retrorectal lesions are rare entities. We report the complete clinicopathological details of an unusual retrorectal lesion composed of low-grade endometrioid adenocarcinoma and propose that this is a malignant change in pluripotent cells arising within a long-standing retrorectal tailgut lesion. To the best of our knowledge, this is the first case report of this malignancy in a retrorectal tailgut cyst.