Banke Agarwal

Induction of gastric epithelial apoptosis by Helicobacter pylori.

BACKGROUND--Helicobacter pylori may promote gastric carcinogenesis through increasing gastric epithelial cell proliferation. How H pylori does so is unknown. Programmed, non-necrotic, cell death (apoptosis) occurs throughout the gut and is linked to proliferation. It was hypothesised that H pylori may induce hyper-proliferation through increasing apoptosis. AIM--To measure the effect of H pylori infection on gastric epithelial apoptosis in situ. PATIENTS--Patients with duodenal ulcers treated to eradicate H pylori and patients with H pylori negative non-ulcer dyspepsia. METHODS--Retrospective quantification of apoptotic epithelial cells in situ from formalin fixed biopsy specimens, counted after staining by terminal uridine deoxynucleotidyl nick end-labelling. RESULTS--In the uninfected stomach, apoptotic cells were rare and situated in the most superficial portion of gastric glands (mean 2.9% of epithelial cells). In H pylori infection, they were more numerous and were located throughout the depth of gastric glands, comprising 16.8% of epithelial cells, falling to 3.1% after H pylori eradication, p = 0.017. Apoptotic cell number did not correlate with the degree of histological gastritis. CONCLUSIONS--These results suggest that H pylori induces epithelial apoptosis in vivo. Increased apoptosis may be the stimulus for a compensatory hyperproliferative and potentially preneoplastic response in chronic H pylori infection.

Lovastatin augments sulindac-induced apoptosis in colon cancer cells and potentiates chemopreventive effects of sulindac

BACKGROUND & AIMS 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (HRIs) were found incidentally to reduce new cases of colon cancer in 2 large clinical trials evaluating coronary events, although most patients in both treatment and control group were taking nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs are associated with reduced colon cancer incidence, predominantly by increasing apoptosis. We showed previously that lovastatin induces apoptosis in colon cancer cells. In the present study we evaluated the potential of combining lovastatin with sulindac for colon cancer chemoprevention. RESULTS Lovastatin, 10-30 micromol/L, augmented sulindac-induced apoptosis up to 5-fold in 3 colon cancer cell lines. This was prevented by mevalonate (100 micromol/L) or geranylgeranylpyrophosphate (10 micromol/L) but not farnesylpyrophosphate (100 micromol/L), suggesting inhibition of geranylgeranylation of target protein(s) as the predominant mechanism. In an azoxymethane rat model of chemical-induced carcinogenesis, the total number of colonic aberrant crypt foci per animal (control, 161 +/- 11) and the number of foci with 4+ crypts (control, 40 +/- 4.5) decreased to 142 +/- 14 (NS) and 43 +/- 2.9 (NS), respectively, with 50 ppm lovastatin alone; to 137 +/- 5.4 (P = 0.053) and 36 +/- 2.1 (NS) with 80 ppm sulindac alone; and to 116 +/- 8.1 (P = 0.004) and 28 +/- 3.4 (P = 0.02) when 50 ppm lovastatin and 80 ppm sulindac were combined. CONCLUSIONS Addition of an HRI such as lovastatin may augment chemopreventive effects of NSAIDs or/and may allow lower, less toxic doses of these drugs to be used.

Cox-2 is needed but not sufficient for apoptosis induced by Cox-2 selective inhibitors in colon cancer cells

The role of Cox-2 in NSAID-induced apoptosis is debated. We studied the role of Cox-2 inhibition in apoptosis induced by a selective Cox-2 inhibitor, SC236 (a structural analogue of celecoxib) in two colon cancer cell lines, HT29 (expressing Cox-2 protein) and HCT116 (not expressing Cox-2 protein). Apoptosis was quantified by flow cytometry. SC236 0–75 μM decreased cell numbers and induced apoptosis to identical levels in HT29 and HCT116 cells. However, SC236, concentrations >75 μM reduced Cox-2 protein expression in HT29 cells and induced greater levels of apoptosis in HT29 than in HCT116 cells. In contrast, sulindac sulfide (SSD) (which inhibits Cox-1 and Cox-2) 0–200 μM or sulindac sulfone (SSN) 0–500 μM (without significant activity against Cox-1 or Cox-2) caused identical decreases in cell number and increases in apoptosis in HT29 and HCT116 cells. Neither SSD nor SSN altered the expression of Cox-2 in HT29 cells. To determine that the higher levels of apoptosis in HT29 cells with SC236 >75 μM were related to decreased Cox-2 protein levels, we decreased Cox-2 protein expression in HT29 cells with curcumin (diferuloylmethane) and studied its effect on SC236-induced apoptosis. Curcumin augmented apoptosis induced by SC236 in HT29 cells but not in Cox-2 lacking HCT116 cells. In conclusion, selective Cox-2 inhibitors can induce apoptosis independent of Cox-2 expression. However they may selectively target cells that express Cox-2 by decreasing their Cox-2 protein expression.

Imaging of pancreatic cancer: An overview

Pancreatic cancer (PaCa) is the fourth leading cause of cancer-related death in the United States. The median size of pancreatic adenocarcinoma at the time of diagnosis is about 31 mm and has not changed significantly in last three decades despite major advances in imaging technology that can help diagnose increasingly smaller tumors. This is largely because patients are asymptomatic till late in course of pancreatic cancer or have nonspecific symptoms. Increased awareness of pancreatic cancer amongst the clinicians and knowledge of the available imaging modalities and their optimal use in evaluation of patients suspected to have pancreatic cancer can potentially help in diagnosing more early stage tumors. Another major challenge in the management of patients with pancreatic cancer involves reliable determination of resectability. Only about 10% of pancreatic adenocarcinomas are resectable at the time of diagnosis and would potentially benefit from a R0 surgical resection. The final determination of resectability cannot be made until late during surgical resection. Failure to identify unresectable tumor pre-operatively can result in considerable morbidity and mortality due to an unnecessary surgery. In this review, we review the relative advantages and shortcomings of imaging modalities available for evaluation of patients with suspected pancreatic cancer and for preoperative determination of resectability.

Survival in pancreatic carcinoma based on tumor size

Objectives: The size of pancreatic tumors that can be diagnosed by preoperative imaging continues to decrease because advances in diagnostic imaging. Several surgical series have suggested that survival is better in tumors 20 mm or smaller (vs tumors >20 mm), but the incremental benefit of diagnosing progressively smaller tumors from 30 mm (currently, the average size of pancreatic tumor at diagnosis) to 20 mm or smaller is not known. We investigated survival and resectability as tumor size increased from 20 mm or smaller to 30 mm or larger. Methods: This is a retrospective analysis of consecutive patients with pancreatic cancer, who underwent endoscopic ultrasound-guided fine-needle aspiration at MD Anderson Cancer Center between December 2000 and December 2001. Tumor size was based on the combination of endoscopic ultrasound and computed tomography imaging. Results: The median (±SE) for tumors 20 mm or smaller, 21 to 25 mm, 26 to 30 mm and larger than 30 mm was 17.2 ± 8.2, 12.3 ± 4.9, 8.5 ± 3.6, and 7.6 ± 1.2 months (P = 0.021), respectively. Tumors were resectable in 10 (83%) of 12 tumors 20 mm or smaller, 8 (67%) of 12 tumors 21 to 25 mm, 5 (36%) of 14 of tumors 26 to 30 mm, and 2 (7%) of 27 tumors larger than 30 mm (P < 0.001). Conclusions: A dramatic change in survival occurs as the size of pancreatic tumor increases from 20 mm or smaller to 30 mm or larger. To be effective, future strategies for early diagnosis of pancreatic cancer should aim at diagnosing most pancreatic cancers before they are 20 mm in size.

Diagnostic value of EUS-FNA in patients suspected of having pancreatic cancer with a focal lesion on CT scan/MRI but without obstructive jaundice.

Objective: Patients frequently present with suspected pancreatic neoplasm based on a focal pancreatic lesion on computed tomographic (CT) scan/magnetic resonance image (MRI) but without obstructive jaundice. We evaluated the performance characteristics of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in this patient subset. Methods: This is a retrospective analysis of a prospective database and included patients who underwent EUS-FNA at a university hospital for a focal pancreatic lesion noted on CT/MRI. Patients were excluded if (1) they had obstructive jaundice or (2) the lesion appear (seem)ed cystic on CT/MRI. The main outcome measurements were (1) prevalence of pancreatic cancer and (2) performance characteristics of EUS-FNA for identifying malignancy. Results: In the 213 study patients, a focal pancreatic lesion was identified in 173 patients by EUS. The final diagnosis included adenocarcinoma (n = 89), neuroendocrine tumor (n = 14), mucinous cystadenocarcinoma (n = 1), solid pseudopapillary tumor (n = 2), metastases (n = 4), benign cyst (n = 19), pseudocyst (n = 9), abscess (n = 4), chronic pancreatitis (n = 32), and normal pancreas (n = 39). Endoscopic ultrasound-guided FNA had an accuracy of 97.6% for diagnosing malignant neoplasm, with 96.6% sensitivity, 99.0% specificity, 96.2% negative predictive value, and 99.1% positive predictive value. Conclusions: Endoscopic ultrasound-guided FNA is highly accurate for diagnosing malignancy in patients with a focal pancreatic lesion on CT scan/MRI but without obstructive jaundice. Endoscopic ultrasound-guided FNA can potentially be used as a definitive diagnostic test in the management of these patients.

Increased Risk of Pancreatic Adenocarcinoma After Acute Pancreatitis

BACKGROUND & AIMS Acute pancreatitis (AP) is often the initial presentation of pancreatic cancer (pancreatic adenocarcinoma [PaCa]). We evaluated the risk of PaCa after AP. METHODS We performed a retrospective study of patients with AP who sought care in the Veterans Health Administration from 1998 through 2007. We excluded patients with pre-existing PaCa or recurrent AP and those who had the first episode of acute pancreatitis, from 1998 through 2000. RESULTS Of 495,504 patients with Veterans Health Administration inpatient and outpatient records, 5720 were diagnosed with AP (1.15%) and 710 were diagnosed with PaCa (0.14%), from 2000 through 2007. Seventy-six patients had AP within 2 years before being diagnosed with PaCa (10.7% of all patients with cancer diagnosed during that period). The risk for PaCa was greatest in the first year after AP (14.5 per 1000 patient-years) and then decreased rapidly. Risk for PaCa was negligible in patients <40 years old. The incidence of PaCa within the first year after AP was 7.69 per 1000 patient-years in fifth decade of life and reached 28.67 after the seventh decade. Time to diagnosis of PaCa after AP was ≤2 months for 34 patients, 3-12 months for 35 patients, 13-24 months for 7 patients, and >24 months for 10 patients. CONCLUSIONS A significant number of patients with PaCa initially present with AP; the diagnosis of cancer is often delayed by up to 2 years. We suggest that PaCa be routinely considered as a potential etiology of AP in patients ≥40 years old.

Patients with obstructive jaundice and biliary stricture ± mass lesion on imaging: prevalence of malignancy and potential role of EUS-FNA.

Background: In patients with obstructive jaundice and biliary stricture, the role of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is debated for fear of missing a potentially resectable pancreatobiliary malignancy (PBM). We evaluated the prevalence of (1) PBM; (2) lesions that do not require a potentially curative cancer surgery; and (3) potentially resectable PBMs in patients with false-negative diagnosis by EUS-FNA. Patients and Methods: This is a retrospective analysis of 342 patients who underwent EUS/EUS-FNA from 2002 to 2009 after presenting with obstructive jaundice and a biliary stricture. Of these, 170 patients had no definitive mass on computed tomography and 172 patients had definitive mass on computed tomography without evidence of unresectability. Final diagnosis was based on surgical pathology or definitive cytology and clinical follow-up of ≥12 months. Results: The mean age of patients (176 male) was 68.0±12.5 years. A final diagnosis of malignancy was made in only 248 patients (72.5%; 95% confidence interval, 67.7, 77.2). The overall accuracy of EUS-FNA for diagnosing malignancy was 92.4% (89.0, 94.8), with 91.5% sensitivity (87.1, 94.5) and 80.9% negative predictive value (72.0, 87.5). Among 21 patients with false-negative diagnosis, 8 had cholangiocarcinoma (2 resectable), 13 had pancreatic cancer (5 resectable). EUS-FNA provided information to potentially modify surgical management in 116 patients (33.9%; 95% confidence interval, 29.1, 39.0): 89 patients diagnosed as true negatives, 24 with distant malignant lymphadenopathy, and 3 with malignant lymphoma. Conclusions: In above-defined patient subset, the risk of missing resectable tumors by EUS-FNA has been exaggerated because of artifactually low negative predictive value resulting from a high pretest probability of PBM. The actual miss rate for resectable PBM by EUS-FNA is rather small and was 2% in present cohort. Information from EUS-FNA can potentially modify surgical management in up to one third of patients.

Malignant mediastinal lymphadenopathy detected by staging EUS in patients with pancreaticobiliary cancer

BACKGROUND In patients with pancreatic cancer, the presence of malignant mediastinal lymphadenopathy (MML) would preclude definitive resection. A recent study suggested routine evaluation for mediastinal lymph-node metastases in all patients being evaluated for pancreaticobiliary masses. In our practice, we routinely assess for mediastinal lymph-node metastases in all patients undergoing EUS for pancreaticobiliary cancer. METHODS We retrospectively evaluated the presence of MML by EUS-guided FNA (EUS-FNA) in 160 consecutive patients with a definite diagnosis of pancreaticobiliary cancer (pancreatic and periampullary cancers) who underwent EUS-FNA by a single operator from 2000 to 2004. Lymph nodes that were round and hypoechoic with sharp margins were considered suspicious and were sampled by FNA. RESULTS Of the 160 patients included in this study, 78 had peripancreatic lymph nodes (49%: 95% CI[41%, 58%]), 25 had celiac lymph nodes (16%: 95% CI[10%, 22%]), and 14 patients had mediastinal lymph nodes (9%: 95% CI[4%, 13%]) that were suspicious for malignancy by morphologic criteria. In 8 of 14 patients with suspicious mediastinal lymph nodes, FNA documented MML in 5%: 95% CI[2%, 8%]. Only one of these 8 patients with MML had other sites of documented distant metastases by CT and/or positron emission tomography scans. However, 7 of 8 patients had locally advanced cancers. CONCLUSIONS MML is detected by staging EUS-FNA in 5% of patients with pancreaticobiliary cancer. Because of its important implications, endosonographers should routinely assess for MML in patients who undergo staging EUS for pancreaticobiliary malignancy.

Immunostaining as an Adjunct to Cytology for Diagnosis of Pancreatic Adenocarcinoma

BACKGROUND & AIMS Serial analysis of gene expression has helped identify several proteins that are expressed differentially in pancreatic cancer and are highly sensitive and specific for pancreatic adenocarcinoma. We evaluated if the diagnostic accuracy of pancreatic cancer from endoscopic ultrasound (EUS)-fine-needle aspiration (FNA) can be improved by combined evaluation of cytology and immunostaining with these markers. METHODS This study involved the use of archived specimens from patients treated at Saint Louis University Hospital from 2002 to 2006. We identified 5 protein markers that appeared most promising from published literature. We sequentially evaluated immunostaining with these markers in (1) surgical resection specimens, (2) cell blocks from EUS-FNA, and (3) direct smears of EUS-FN aspirates. Finally, we performed a combined evaluation of cytology and immunostaining in direct smears that were difficult to interpret and required a second consultative cytologic opinion. RESULTS In resection specimens, the majority of pancreatic adenocarcinomas expressed all 5 markers but fascin, maspin, and carcinoembryonic antigen-related cell adhesion molecule 6 also were expressed abnormally in normal pancreata and in chronic pancreatitis. Further evaluation therefore was limited to the other 2 markers: mesothelin and 14-3-3sigma. It was feasible and useful to perform immunostaining in cell blocks and direct smear for diagnosing pancreatic cancer. In cases requiring a second cytologic consultation, a combined evaluation of cytologic morphology and immunostaining had 90% accuracy for a pancreatic adenocarcinoma diagnosis. CONCLUSIONS In conclusion, immunostaining with newer protein markers is feasible in EUS-FNA specimens and can assist cytopathologists in diagnosing pancreatic cancer. Among the currently available protein immunomarkers, a combination of mesothelin and 14-3-3sigma seems most promising, but needs to be validated in prospective studies before routine clinical use.