Asif Rashid

One hundred years after "carcinoid": epidemiology of and prognostic factors for neuroendocrine tumors in 35,825 cases in the United States.

PURPOSE Neuroendocrine tumors (NETs) are considered rare tumors and can produce a variety of hormones. In this study, we examined the epidemiology of and prognostic factors for NETs, because a thorough examination of neither had previously been performed. METHODS The Surveillance, Epidemiology, and End Results (SEER) Program registries were searched to identify NET cases from 1973 to 2004. Associated population data were used for incidence and prevalence analyses. Results We identified 35,618 patients with NETs. We observed a significant increase in the reported annual age-adjusted incidence of NETs from 1973 (1.09/100,000) to 2004 (5.25/100,000). Using the SEER 9 registry data, we estimated the 29-year limited-duration prevalence of NETs on January 1, 2004, to be 9,263. Also, the estimated 29-year limited-duration prevalence in the United States on that date was 103,312 cases (35/100,000). The most common primary tumor site varied by race, with the lung being the most common in white patients, and the rectum being the most common in Asian/Pacific Islander, American Indian/Alaskan Native, and African American patients. Additionally, survival duration varied by histologic grade. In multivariate analysis of patients with well-differentiated to moderately differentiated NETs, disease stage, primary tumor site, histologic grade, sex, race, age, and year of diagnosis were predictors of outcome (P < .001). CONCLUSION We observed increased reported incidence of NETs and increased survival durations over time, suggesting that NETs are more prevalent than previously reported. Clinicians need to be become familiar with the natural history and patterns of disease progression, which are characteristic of these tumors.

Simplified Staging for Hepatocellular Carcinoma

PURPOSE The current American Joint Committee on Cancer (AJCC) staging system for hepatocellular carcinoma (HCC) fails to stratify patients adequately with respect to prognosis. PATIENTS AND METHODS The ability of the currently proposed tumor (T) categories to effectively stratify the survival of 557 patients who underwent complete resection for HCC at four centers was examined. Independent predictors of survival were combined into a new staging system. RESULTS Using the current AJCC T classification, patients with T1 and T2 tumors had similar 5-year survivals (P =.6). In addition, the survival of patients with multiple bilobar tumors (T4) matched that of T3 patients (P =.5). Independent predictors of death were major vascular invasion (P <.001), microvascular invasion (P =.001), severe fibrosis/cirrhosis of the host liver (P =.001), multiple tumors (P =.007), and tumor size greater than 5 cm (P =.01). Based on our results, a simplified stratification is proposed: (a) patients with a single tumor and no microvascular invasion, (b) patients with a single tumor and microvascular invasion or multiple tumors, none more than 5 cm, and (c) patients with either multiple tumors, any more than 5 cm, or tumor with major vascular invasion (P <.001). Severe fibrosis/cirrhosis had a negative impact on survival within all categories. The survival of patients with lymph node involvement matched that of patients with major vascular invasion (P =.3). CONCLUSION The current AJCC staging system for HCC is unnecessarily complex. We propose a simplified model of stratification that is based on vascular invasion, tumor number, and tumor size and incorporates the effect of fibrosis on survival.

Efficacy of RAD001 (Everolimus) and Octreotide LAR in Advanced Low- to Intermediate-Grade Neuroendocrine Tumors: Results of a Phase II Study

PURPOSE Evaluate the activity of everolimus (RAD001) in combination with octreotide long-acting repeatable (LAR) in patients with advanced low- to intermediate-grade neuroendocrine tumors. METHODS Treatment consisted of RAD001 5 mg/d (30 patients) or 10 mg/d (30 patients) and octreotide LAR 30 mg every 28 days. Thirty carcinoid and 30 islet cell patients were enrolled. RESULTS Intent-to-treat response rate was 20%. Per protocol, there were 13 with partial responses (22%), 42 with stable disease (SD; 70%), and five patients with progressive disease (8%). Overall median progression-free survival (PFS) was 60 weeks. Median PFS for patients with known SD at entry was longer than for those who had progressive disease (74 v 50 weeks; P < .01). Median overall survival has not been reached. One-, 2-, and 3-year survival rates were 83%, 81%, and 78%, respectively. Among 37 patients with elevated chromogranin A, 26 (70%) achieved normalization or more than 50% reduction. Most common toxicity was mild aphthous ulceration. Grade 3/4 toxicities occurring in >or= 10% of patients included hypophosphatemia (11%), fatigue (11%), and diarrhea (11%). Treatment was associated with a dose-dependent rise in lactate dehydrogenase (LDH). Those with lower than 109 U/L rise in LDH at week 4 had shorter PFS (38 v 69 weeks; P = .01). Treatment was also associated with a decrease in proliferation marker Ki-67 among patients who underwent optional paired pre- and post-treatment biopsy (P = .04). CONCLUSION RAD001 at 5 or 10 mg/d was well tolerated in combination with octreotide LAR, with promising antitumor activity. Confirmatory studies are ongoing.

OBESITY INDUCES EXPRESSION OF UNCOUPLING PROTEIN-2 IN HEPATOCYTES AND PROMOTES LIVER ATP DEPLETION

Uncoupling protein 2 (UCP2) uncouples respiration from oxidative phosphorylation and may contribute to obesity through effects on energy metabolism. Because basal metabolic rate is decreased in obesity, UCP2 expression is predicted to be reduced. Paradoxically, hepatic expression of UCP2 mRNA is increased in genetically obese (ob/ob) mice. In situ hybridization and immunohistochemical analysis of ob/ob livers demonstrate that UCP2 mRNA and protein expression are increased in hepatocytes, which do not express UCP2 in lean mice. Mitochondria isolated from ob/ob livers exhibit an increased rate of H+ leak which partially dissipates the mitochondrial membrane potential when the rate of electron transport is suppressed. In addition, hepatic ATP stores are reduced and these livers are more vulnerable to necrosis after transient hepatic ischemia. Hence, hepatocytes adapt to obesity by up-regulating UCP2. However, because this decreases the efficiency of energy trapping, the cells become vulnerable to ATP depletion when energy needs increase acutely.

Histopathological Identification of Colon Cancer with Microsatellite Instability

Cancer with high levels of microsatellite instability (MSI-H) is the hallmark of hereditary nonpolyposis colorectal cancer syndrome, and MSI-H occurs in approximately 15% of sporadic colorectal carcinomas that have improved prognosis. We examined the utility of histopathology for the identification of MSI-H cancers by evaluating the features of 323 sporadic carcinomas using specified criteria and comparing the results to MSI-H status. Coded hematoxylin and eosin sections were evaluated for tumor features (signet ring cells; mucinous histology; cribriforming, poor differentiation, and medullary-type pattern; sponge-like mucinous growth; pushing invasive margin) and features of host immune response (Crohns-like lymphoid reaction, intratumoral lymphocytic infiltrate, and intraepithelial T cells by immunohistochemistry for CD3 with morphometry). Interobserver variation among five pathologists was determined. Subjective interpretation of histopathology as an indication for MSI testing was recorded. We found that medullary carcinoma, intraepithelial lymphocytosis, and poor differentiation were the best discriminators between MSI-H and microsatellite-stable cancers (odds ratio: 37.8, 9.8, and 4.0, respectively; P = 0.000003 to < 0.000001) with high specificity (99 to 87%). The sensitivities, however, were very low (14 to 38%), and interobserver agreement was good only for evaluation of poor differentiation (kappa, 0.69). Mucinous histopathological type and presence of signet ring cells had low odds ratios of 3.3 and 2.7 (P = 0.005 and P = 0.02) with specificities of 95% but sensitivities of only 15 and 13%. Subjective interpretation of the overall histopathology as suggesting MSI-H performed better than any individual feature; the odds ratio was 7.5 (P < 0.000001) with sensitivity of 49%, specificity of 89%, and moderate interobserver agreement (kappa, 0.52). Forty intraepithelial CD3-positive lymphocytes/0.94 mm2, as established by receiver operating characteristic curve analysis, resulted in an odds ratio of 6.0 (P < 0.000001) with sensitivity of 75% and specificity of 67%. Our findings indicate that histopathological evaluation can be used to prioritize sporadic colon cancers for MSI studies, but morphological prediction of MSI-H has low sensitivity, requiring molecular analysis for therapeutic decisions.

Posttherapy pathologic stage predicts survival in patients with esophageal carcinoma receiving preoperative chemoradiation

In patients with locoregional carcinoma of the esophagus or esophagogastric junction who underwent preoperative chemoradiation, it is unclear whether survival was better predicted by pretherapy clinical stage or by posttherapy pathologic stage.

Phase 2 study of erlotinib in patients with unresectable hepatocellular carcinoma

Growth factor overexpression, including epidermal growth factor receptor (EGFR) expression, is common in hepatocellular cancers. Erlotinib is a receptor tyrosine kinase inhibitor with specificity for EGFR. The primary objective of this study was to determine the proportion of hepatocellular carcinoma (HCC) patients treated with erlotinib who were alive and progression‐free (PFS) at 16 weeks of continuous treatment.

Progenitor/stem cells give rise to liver cancer due to aberrant TGF-β and IL-6 signaling

Cancer stem cells (CSCs) are critical for the initiation, propagation, and treatment resistance of multiple cancers. Yet functional interactions between specific signaling pathways in solid organ “cancer stem cells,” such as those of the liver, remain elusive. We report that in regenerating human liver, two to four cells per 30,000–50,000 cells express stem cell proteins Stat3, Oct4, and Nanog, along with the prodifferentiation proteins TGF-β-receptor type II (TBRII) and embryonic liver fodrin (ELF). Examination of human hepatocellular cancer (HCC) reveals cells that label with stem cell markers that have unexpectedly lost TBRII and ELF. elf+/− mice spontaneously develop HCC; expression analysis of these tumors highlighted the marked activation of the genes involved in the IL-6 signaling pathway, including IL-6 and Stat3, suggesting that HCC could arise from an IL-6-driven transformed stem cell with inactivated TGF-β signaling. Similarly, suppression of IL-6 signaling, through the generation of mouse knockouts involving a positive regulator of IL-6, Inter-alpha-trypsin inhibitor-heavy chain-4 (ITIH4), resulted in reduction in HCC in elf+/− mice. This study reveals an unexpected functional link between IL-6, a major stem cell signaling pathway, and the TGF-β signaling pathway in the modulation of mammalian HCC, a lethal cancer of the foregut. These experiments suggest an important therapeutic role for targeting IL-6 in HCCs lacking a functional TGF-β pathway.

CpG Island Methylation in Aberrant Crypt Foci of the Colorectum

Aberrant crypt foci (ACF) are postulated to be the earliest precursor lesion in colorectal carcinogenesis, and CpG island methylation has been described as an important molecular pathway. We therefore studied methylation in ACF from patients with familial adenomatous polyposis (FAP) or sporadic colorectal cancer. We assessed methylation status of the p16 tumor suppressor gene, MINT1 (methylated in tumor 1), MINT2, MINT31, O(6)-methylguanine-DNA methyltransferase gene, and hMLH1 mismatch repair gene. We compared methylation to ACF histopathology, K-ras proto-oncogene mutation, loss of heterozygosity at chromosome 1p, and microsatellite instability. Methylation was present in 34% (21 of 61) of ACF, including both FAP and sporadic types, but was more frequent in sporadic ACF [53% (18 of 34) versus 11% (3 of 27), P = 0.002], especially dysplastic sporadic ACF [75% (3 of 4) versus 8% (2 of 24), P = 0.004]. MINT31 was more frequently methylated in heteroplastic ACF than dysplastic ACF [35% (11 of 31) versus 7% (2 of 30), P = 0.01]. Strong associations of ACF methylation with K-ras mutation (P = 0.007) and with loss of chromosome 1p (P = 0.04) were observed, but methylation was the only molecular abnormality identified in 16% (10 of 61) of ACF. Our findings suggest that methylation in ACF is an early event in the pathogenesis of a subset of colorectal carcinomas, and that ACF from FAP patients and patients with sporadic colorectal cancer have distinct epigenetic changes that reflect differences in molecular pathogenesis.

Population-based study of islet cell carcinoma

BackgroundWe examine the epidemiology, natural history, and prognostic factors that affect the duration of survival for islet cell carcinoma by using population-based registries.MethodsThe Surveillance, Epidemiology, and End Results (SEER) Program database (1973–2003 release, April 2006) was used to identify cases of islet cell carcinoma by histology codes and tumor site.ResultsA total of 1310 (619 women and 691 men) cases with a median age of 59 years were identified. The annual age-adjusted incidence in the periods covered by SEER 9 (1973–1991), SEER 13 (1992–1999), and SEER 17 (2000–2003) were .16, .14, and .12 per 100,000, respectively. The estimated 28-year limited duration prevalence on January 1, 2003, in the United States was 2705 cases. Classified by SEER stage, localized, regional, and distant stages corresponded to 14%, 23%, and 54% of cases. The median survival was 38 months. By stage, median survival for patients with localized, regional, and distant disease were 124 (95% CI, 80–168) months, 70 (95% CI, 54–86) months, and 23 (95% CI, 20–26) months, respectively. By multivariate Cox proportional modeling, stage (P < .001), primary tumor location (P = .04), and age at diagnosis (P < .001) were found to be significant predictors of survival.ConclusionsIslet cell carcinomas account for approximately 1.3% of cancers arising in the pancreas. Most patients have advanced disease at the time of diagnosis. Despite the disease’s reputation of being indolent, survival of patients with advanced disease remains only 2 years. Development of novel therapeutic approaches is needed.