Ampullary and periampullary tumors: translational efforts to meet a challenge in diagnosis and treatment. Highlights from the "2011 ASCO Gastrointestinal Cancers Symposium". San Francisco, CA, USA. January 20-22, 2011.

Ampullary adenocarcinoma is a rare diagnosis and often managed as carcinomas of pancreatobiliary origin. However, there is accumulating evidence unveiling attributes of ampullary carcinomas that are distinct from that of pancreas or biliary cancers. Growing translational efforts in understanding this rare disease are exemplified by Abstracts #161 and #204 presented at the 2011 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium.

A pharmacogenetic study of vorinostat glucuronidation.

High interindividual pharmacokinetic variability was observed in phase 1 studies of vorinostat (suberoylanilide hydroxamic acid), an oral histone deacetylase inhibitor. Thus, we hypothesized that the variability can be explained by genetic variants of the uridine 5'-diphosphate-glucuronosyltransferases (UGTs) involved in vorinostat metabolism. Baculosomes expressing human UGTs and 52 human liver microsomes were screened for vorinostat glucuronidation activity to identify the potential enzymes and functional variants. UGT2B17 had the largest activity. Human liver microsomes with at least one copy of UGT2B17 showed significantly greater enzymatic activity than those with UGT2B17 null genotype (P<0.004). UGT2B17 plays an important role in vorinostat hepatic glucuronidation and the gene deletion polymorphism may influence vorinostat biotransformation and clearance. The clinical impact of this UGT2B17 genetic variant on vorinostat metabolism and drug effect is unknown.

Clinical outcome of pancreatic cancer patients with diabetes mellitus: is diabetes a poor prognostic factor? Highlights from the "2010 ASCO Annual Meeting". Chicago, IL, USA. June 4-8, 2010.

Diabetes mellitus and its related factors such as hyperinsulinemia have been linked to various cancer risks and outcomes. Previous research has offered inconsistent results in terms of relationship between diabetes and pancreatic cancers. Establishing clear association between these two entities may guide us in improving clinical outcomes of pancreatic cancer patients. Two abstracts that examined the association between diabetes mellitus and pancreatic cancer are updated in this paper. Herein, the authors report updated information from the 2010 American Society of Clinical Oncology (ASCO) Annual Meeting in association between pancreatic cancer and diabetes mellitus. The present paper illustrates insufficient knowledge base to draw a conclusion in this topic. However, validation and understanding of the association could have significant clinical implications with respect to cancer prevention, early detection, and treatment. As such, further investigations are warranted to explore the link diabetes and pancreatic cancers.

Biophysical and Immunological Characterization and In Vivo Pharmacokinetics and Toxicology in Nonhuman Primates of the Anti-PD-1 Antibody Pembrolizumab.

The programmed cell death 1 (PD-1) pathway represents a major immune checkpoint, which may be engaged by cells in the tumor microenvironment to overcome active T-cell immune surveillance. Pembrolizumab (Keytruda®, MK-3475) is a potent and highly selective humanized mAb of the IgG4/kappa isotype designed to directly block the interaction between PD-1 and its ligands, PD-L1 and PD-L2. This blockade enhances the functional activity of T cells to facilitate tumor regression and ultimately immune rejection. Pembrolizumab binds to human and cynomolgus monkey PD-1 with picomolar affinity and blocks the binding of human and cynomolgus monkey PD-1 to PD-L1 and PD-L2 with comparable potency. Pembrolizumab binds both the C'D and FG loops of PD-1. Pembrolizumab overcomes human and cynomolgus monkey PD-L1-mediated immune suppression in T-cell cultures by enhancing IL2 production following staphylococcal enterotoxin B stimulation of healthy donor and cancer patient cells, and IFNγ production in human primary tumor histoculture. Ex vivo and in vitro studies with human and primate T cells show that pembrolizumab enhances antigen-specific T-cell IFNγ and IL2 production. Pembrolizumab does not mediate FcR or complement-driven effector function against PD-1-expressing cells. Pembrolizumab displays dose-dependent clearance and half-life in cynomolgus monkey pharmacokinetic and toxicokinetic studies typical for human IgG4 antibodies. In nonhuman primate toxicology studies, no findings of toxicologic significance were observed. The preclinical data for pembrolizumab are consistent with the clinical anticancer activity and safety that has been demonstrated in human clinical trials.

Global variation in CYP2C8-CYP2C9 functional haplotypes.

We have studied the global frequency distributions of 10 single nucleotide polymorphisms (SNPs) across 132 kb of CYP2C8 and CYP2C9 in approximately 2500 individuals representing 45 populations. Five of the SNPs were in noncoding sequences; the other five involved the more common missense variants (four in CYP2C8, one in CYP2C9) that change amino acids in the gene products. One haplotype containing two CYP2C8 coding variants and one CYP2C9 coding variant reaches an average frequency of 10% in Europe; a set of haplotypes with a different CYP2C8 coding variant reaches 17% in Africa. In both cases these haplotypes are found in other regions of the world at <1%. This considerable geographic variation in haplotype frequencies impacts the interpretation of CYP2C8/CYP2C9 association studies, and has pharmacogenomic implications for drug interactions.

Circulating tumor cells in HER-2 positive metastatic breast cancer patients treated with trastuzumab and chemotherapy.

The detection of circulating tumor cells (CTCs) in peripheral blood may have important prognostic and predictive implications in breast cancer treatment. A limitation in this field has been the lack of a validated method of accurately measuring CTCs. While sensitivity has improved using RT-PCR, specificity remains a major challenge. The goal of this paper is to present a sensitive and specific methodology of detecting CTCs in women with HER-2 positive metastatic breast cancer, and to examine its role as a marker that tracks disease response during treatment with trastuzumab-containing regimens. The study included patients with HER-2-positive metastatic breast cancer enrolled on two different clinical protocols using a trastuzumab-containing regimen. Serial CTCs were measured at planned time points and clinical correlations were made. Immunomagnetic selection of circulating epithelial cells was used to address the specificity of tumor cell detection using cytokeratin 19 (CK19). In addition, the extracellular domain of the HER-2 protein (HER-2/ECD) was measured to determine if CTCs detected by CK19 accurately reflect tumor burden. The presence of CTCs at first restaging was associated with disease progression. We observed an association between CK19 and HER-2/ECD. The association of HER-2/ECD with clinical response followed a similar pattern to that seen with CK19. Finally, the absence of HER-2/ECD at best overall response and a change of HER-2/ECD from positive at baseline to negative at best overall response was associated with favorable treatment response. Our study supports the prognostic and predictive role of the detection of CTCs in treatment of HER-2-positive metastatic breast cancer patients. The association between CK19 and markers of disease burden is in line with the concept that CTCs may be a reliable measure of tumor cells in the peripheral blood of patients with metastatic breast cancer. The association of CTCs at first restaging with treatment failure indicates that CTCs may have a role as surrogate markers to monitor treatment response.

Pseudocirrhosis in a pancreatic cancer patient with liver metastases: a case report of complete resolution of pseudocirrhosis with an early recognition and management.

We report a case of pseudocirrhosis arising in the setting of regression of liver metastases from pancreatic cancer. A 55-year-old asymptomatic woman presented to our clinic with newly diagnosed metastatic pancreatic cancer with extensive liver metastases. She underwent systemic chemotherapy with gemcitabine and oxaliplatin (GEMOX). After 8 cycles of therapy, she had a remarkable response to the therapy evidenced by decline of carcinoembryonic antigen (CEA) and CA19 by > 50% and nearly complete resolution of hepatic metastases in computed tomography (CT) scan. Shortly after, she developed increasing bilateral ankle edema and ascites, associated with dyspnea, progressive weight gain, and declining performance status. Gemcitabine and oxaliplatin were discontinued as other causes of her symptoms such as congestive heart disease or venous thrombosis were ruled out. CT scan 6 mo after the initiation of GEMOX revealed worsening ascites with a stable pancreatic mass. However, it also revealed a lobular hepatic contour, segmental atrophy, and capsular retraction mimicking the appearance of cirrhosis. She was managed with aggressive diuresis and albumin infusions which eventually resulted in a resolution of the above-mentioned symptoms as well as complete resolution of pseudocirrhotic appearance of the liver and ascites in CT scan. This case demonstrates that pancreatic cancer patients can develop pseudocirrhosis. Clinicians and radiologist should be well aware of this entity as early recognition and management can lead to a near complete recovery of liver function and much improved quality of life as illustrated in this case.

Pharmacogenomics and pancreatic cancer treatment. Optimizing current therapy and individualizing future therapy.

Each year, more than 30,000 Americans are diagnosed with pancreatic cancer. We have only made incremental advancements in treatment of pancreatic cancer despite our best efforts. Research has revealed that pancreatic cancer is a genetic disease which is associated with various forms of cancer associated genetic alterations. Identification and understanding of these carcinogenic gene alterations is the base upon which we can overcome drug resistance and develop novel treatment approaches. In this paper, we review current understanding of pharmacogenomics of pancreatic cancer treatment and address future direction of the field.

Long-term survival on capecitabine in two gemcitabine refractory pancreatic cancer patients. Is there a pharmacogenetic explanation?

CONTEXT: Capecitabine has shown efficacy in treatment of metastatic pancreatic cancer. Several researchers have identified thymidine phosphorylase, dihydropyrimidine dehydrogenase, or their ratio as indicators of response to capecitabine in various cancers. CASE REPORT: We report two patients with metastatic pancreatic carcinoma who had long-term survivals on capecitabine after gemcitabine failure. These two cases prompted us to measure thymidine phosphorylase and dihydropyrimidine dehydrogenase levels to facilitate discourses regarding their relationship with efficacy of capecitabine. We also describe a novel method of measuring thymidine phosphorylase level from serum without an invasive tissue biopsy. One patient is alive as of today, with improved performance status, 50 months after capecitabine was started. CA 19-9 and CT scans remained stable during 57 cycles. Her thymidine phosphorylase level was 1.77 compared to a control level of 1.00. Dihydropyrimidine dehydrogenase level was 4.14 compared to a control level of 1.00. Their ratio was 0.43. The other patient was alive on capecitabine for 24 months. His performance status, bilirubin, AST, and ALT improved on capecitabine. CT scans and CA 19-9 remained stable during this period. He had thymidine phosphorylase level of 5.56, dihydropyrimidine dehydrogenase level of 2.74, and their ratio of 2.03. CONCLUSION: Capecitabine resulted in long term survivals in two patients with metastatic pancreatic cancer after gemcitabine failure. The use of capecitabine as second-line treatment in metastatic pancreatic cancer should be further explored along with the role of thymidine phosphorylase and dihydropyrimidine dehydrogenase levels in its activity. A non-invasive method of thymidine phosphorylase measurement we described should be validated in larger trials.