Genome-wide association study in a Chinese population identifies a susceptibility locus for type 2 diabetes at 7q32 near PAX4

AIMS/HYPOTHESIS

Most genetic variants identified for type 2 diabetes have been discovered in European populations. We performed genome-wide association studies (GWAS) in a Chinese population with the aim of identifying novel variants for type 2 diabetes in Asians.

METHODS

We performed a meta-analysis of three GWAS comprising 684 patients with type 2 diabetes and 955 controls of Southern Han Chinese descent. We followed up the top signals in two independent Southern Han Chinese cohorts (totalling 10,383 cases and 6,974 controls), and performed in silico replication in multiple populations.

RESULTS

We identified CDKN2A/B and four novel type 2 diabetes association signals with p < 1 × 10(-5) from the meta-analysis. Thirteen variants within these four loci were followed up in two independent Chinese cohorts, and rs10229583 at 7q32 was found to be associated with type 2 diabetes in a combined analysis of 11,067 cases and 7,929 controls (p meta = 2.6 × 10(-8); OR [95% CI] 1.18 [1.11, 1.25]). In silico replication revealed consistent associations across multiethnic groups, including five East Asian populations (p meta = 2.3 × 10(-10)) and a population of European descent (p = 8.6 × 10(-3)). The rs10229583 risk variant was associated with elevated fasting plasma glucose, impaired beta cell function in controls, and an earlier age at diagnosis for the cases. The novel variant lies within an islet-selective cluster of open regulatory elements. There was significant heterogeneity of effect between Han Chinese and individuals of European descent, Malaysians and Indians.

CONCLUSIONS/INTERPRETATION

Our study identifies rs10229583 near PAX4 as a novel locus for type 2 diabetes in Chinese and other populations and provides new insights into the pathogenesis of type 2 diabetes.

Long-term follow-up of a phase III study comparing radiotherapy with or without weekly oxaliplatin for locoregionally advanced nasopharyngeal carcinoma

BACKGROUND

Previous results from our trial showed that adding oxaliplatin to radiotherapy (RT) increased survival in patients with locoregionally advanced nasopharyngeal carcinoma (NPC) at 2 years. Here, we present the data of long-term efficacy and late toxic effects.

PATIENTS AND METHODS

Between January 2001 and January 2003, 115 Patients with nonkeratinizing/undifferentiated locoregionally advanced NPC were randomly to receive either RT alone (n = 56) or plus concurrent oxaliplatin 70 mg/m(2) weekly for six cycles (n = 59).

RESULTS

After a median follow-up of 114 months (range 18-139 months), the 5-year overall survival (OS) and metastasis-free survival (MFS) rates in the concurrent chemoradiotherapy (CCRT) group were significantly higher than those observed in the RT-alone group (OS, 73.2% versus 60.2%, P = 0.028; MFS, 74.7% versus 63.0%, P = 0.027). However, CCRT did not improve locoregional failure-free survival significantly. Subgroup analyses showed that the superiorities of CCRT mainly existed in the T3-4N0-1 stage subgroup (OS: HR = 0.394, P = 0.034). The grade 3/4 late toxic effects were similar in the two groups.

CONCLUSION(S)

The long-term follow-up data confirms the role of CCRT as a treatment of locoregionally advanced NPC. Oxaliplatin can be considered as an alternative optional therapeutic regimen for these patients due to its high efficiency and low toxic effect.

Genetic analysis of human predisposition to hepatosplenic disease caused by schistosomes reveals the crucial role of connective tissue growth factor in rapid progression to severe hepatic fibrosis

Schistosome worms inhabit mammalian mesenteric veins. Their eggs cause chronic inflammation, which progresses to periportal fibrosis in 5 to 30% of cases, increasing portal blood pressure and leading to esophageal varices. Episodes of bleeding cause hepatic necrosis and may ultimately lead to hepatic failure and the death of the patient. Schistosome infections can also cause pulmonary hypertension and heart failure. The mechanisms of fibrogenesis and fibrolysis are beginning to be unraveled, but it remains unclear why disease occurs only in certain subjects, as also observed for other types of chronic liver inflammation, as in hepatitis C or B. We summarize here the results that showed that fibrosis progression is determined by a genetic locus on chromosome 6. The CCN2 gene at this locus, encodes CTGF that is a crucial regulator of fibrosis. Two groups of CCN2 polymorphisms independently modulate the progression of hepatic fibrosis. These results were obtained in an Asian population, but were extended to humans living in Africa and South America and are presently tested in liver fibrosis of other etiological origins.

Influence of the catheter diameter on the investigation of the esophageal motility through solid-state high-resolution manometry

Past studies have shown that catheter diameter is one of the device-dependent problems which influence the manometric results in the conventional water perfusion esophageal manometry. High-resolution solid-state manometry which abandons water perfusion is thought as an improved manometry method benefited from more pressure sensors, and it is gradually widely used in many present esophageal motility studies. There was no research to evaluate the influence of catheter diameter on the solid-state high-resolution manometry results. The aim of this study was to investigate whether solid-state high-resolution catheters of different diameter provide different data and results. Nine asymptomatic volunteers and 18 gastroesophageal reflux disease patients accepted high-resolution manometry examinations with two solid-state catheters of different outer diameter (4.2 mm and 2.7 mm). Every examination contained 5 minutes resting pressure, 10 water swallows and 10 bread swallows. Some important parameters of the esophageal sphincters and esophageal body peristalsis were analyzed. They included the locations and resting pressure of sphincters, the distal contractile integral, the 4-second integrated relaxation pressure etc. Then, these parameters and the diagnosis of each swallow based on them provided by the two different diameter catheters were compared. (i) The 4.2 mm thick catheter provided higher upper esophageal sphincter resting pressure than the 2.7 mm thick catheter (59.4 ± 21.1 mmHg vs. 49.7 ± 21.4 mmHg); (ii) the 2.7 mm thick catheter provided higher 4-second integrated relaxation pressure than the 4.2 mm thick catheter (10.9 ± 4.5 mmHg vs. 8.5 ± 3.8 mmHg) in water swallows; (iii) the mean distal contractile integral of the water and bread swallows in the large diameter catheter were higher than in the small diameter catheter (989.2 ± 650.0 mmHg/cm/s vs. 806.3 ± 563.7 mmHg/cm/s in water swallows, 1762.5 ± 1440.6 mmHg/cm/s vs. 1275.7 ± 982.0 mmHg/cm/s in bread swallows); (iv) on the lower esophageal sphincter resting pressure, most parameters in bread swallows provided by the two catheters were of no statistical significance; (v) the 2.7 mm thick catheter detected more hypotensive peristalsis swallows than the other catheter in water swallows; and (vi) the final diagnosis of about half of the subjects provided by the two catheters were different. The 2.7 mm thick solid-state high-resolution manometry catheter provides somewhat different data from the usually used 4.2 mm thick catheter. It is needed to set up different and independent series of normative value for the solid-state high-resolution manometry catheters of different outer diameter. The normative value and diagnostic criterion got from one catheter is not universal and acceptable for researches with catheter of different diameter.

Prucalopride in the treatment of chronic constipation in patients from the Asia-Pacific region: a randomized, double-blind, placebo-controlled study

BACKGROUND

The study evaluated efficacy and safety of the 2 mg dose of prucalopride compared to placebo in patients with chronic constipation (CC) from the Asia-Pacific region.

METHODS

Randomized, placebo-controlled, parallel-group, phase III study with 2-week run-in, 12-week treatment phase, and 1-week follow-up. Adult patients with CC (≤2 spontaneous bowel movements per week) received 2 mg prucalopride or placebo, once-daily, for 12 weeks. Primary efficacy measure was percentage of patients with average of ≥3 spontaneous complete bowel movements (SCBMs) per week (Responders) during the 12-week treatment. A key secondary endpoint was Responders during first 4 weeks of treatment. Other efficacy assessments were based on patient diaries, their assessments of symptoms and quality of life, and investigator's assessment on efficacy of treatment. Safety assessments included adverse events, laboratory values, and cardiovascular events.

KEY RESULTS

Efficacy and safety were evaluated for 501 patients who received study drug. On the primary endpoint, prucalopride was significantly more effective than placebo with 83 (33.3%) vs 26 (10.3%) patients having a weekly average of ≥3 SCBMs during the 12-week treatment (P < 0.001). Respective percentages were 34.5%vs 11.1% over first 4 weeks (P < 0.001). On other secondary endpoints, clinical improvement was generally larger and statistically superior (P < 0.001) in the prucalopride group. Most frequently reported adverse events were diarrhea, nausea, abdominal pain, and headache.

CONCLUSION & INFERENCES

Prucalopride 2 mg given once-daily significantly improved bowel function, associated symptoms, and satisfaction in CC over a 12-week treatment period, and was safe and well tolerated by patients in the Asia-Pacific region.

Increased signal transducer and activator of transcription 3 (STAT3) and decreased cyclin D1 in recurrent astrocytic tumours compared with paired primary astrocytic tumours

This study compared the levels of signal transducer and activator of transcription 3 (STAT3) and cyclin D1 protein in paired primary and recurrent astrocytic tumours, and analysed their correlation with clinicopathological and treatment factors. A total of 48 samples from 24 patients who had undergone surgical removal of primary and recurrent astrocytic tumours were analysed. Levels of STAT3 and cyclin D1 protein were detected using immunohistochemistry. Increased STAT3 and decreased cyclin D1 levels were observed in recurrent astrocytic tumours compared with their paired primary tumours. There was a significant correlation between higher levels of STAT3 protein and shorter progression-free survival in primary tumours after surgery (r = 0.417), and a significant correlation between decreased cyclin D1 protein levels and radiotherapy in recurrent tumours (r = 0.468). It was concluded that increased STAT3 and decreased cyclin D1 protein levels may contribute to the recurrence of astrocytic tumours. Detection of STAT3 may be useful in predicting progressionfree survival in primary astrocytic tumours after surgery. In addition, radiotherapy may decrease cyclin D1 levels in astrocytic tumours, but the nature of this association requires further investigation.

PD01-06: Endoxifen Exhibits Potent Anti-Tumor Activity and Regulates Different Genes Than Tamoxifen in an Aromatase Expressing MCF7 Model Resistant to Letrozole

Background: First in human studies of Z-endoxifen hydrochloride (E), the active metabolite of tamoxifen (T), are underway in metastatic breast cancer (BC). Previous data have demonstrated the superiority of aromatase inhibitors (AI's) over T in estrogen receptor (ER) + BC. Using an in vivo aromatase expressing model (MCF7/AC1), we compared the antitumor activity of E with T and Letrozole (L), as well as the antitumor activity and global gene expression changes of E with T in an L-resistant model.

Methods: MCF7/AC1 tumors were stimulated with androstenedione. Once tumor size reached 300 mm3, mice (30/group) were randomly assigned to one of five treatment groups: control (daily, po), T (500 μg/day, sc), endoxifen 25 mg/kg/day p.o.(LDE) endoxifen 75 mg/kg/day p.o. (HDE) or letrozole, 10 μg/day s.c for 4 weeks. Tumors were harvested from control, T, and E groups while the L group continued treatment until the development of resistance defined as an increase in tumor volume of at least 300% from day 1. Mice with L-resistant tumors were randomly assigned to T (n=4) or E (n=5) for 4 weeks and then sacrificed. Gene expression in L-resistant tumors was quantified using Affymetrix U133+2 and changes in gene expression profiles [comparing T and E with L-resistant (n=3)] were analyzed. Genes identified as significantly different were confirmed by real-time RT-PCR assays.

Results: At the 4 week time point, both doses of E and L resulted in greater anti-tumor activity than control (Wilcoxon rank sum test: all p &lt; 0.0001); however, tumor burden did not differ between T and control (p=0.095). HDE resulted in significantly less tumor burden than T (p=0.002) but was similar to L. In mice that continued on L, resistance developed at 24 weeks in 9/25 mice. These mice were randomly assigned to either T (n=4) or E (n=5) for 4 weeks. Tumor volume (expressed as a% of its size prior to randomization) was significantly different comparing E (73.3%; range: 69.3 to 80.75%) versus T (148.39%; range: 114.07 to 165.99%) (Wilcoxon rank sum test p=0.016). Compared to control, microarray studies identified 1518 unique probe sets regulated by E (p&lt;0.001) compared to 441 for T including estrogen-regulated genes such as progesterone receptor (PGR) and amphiregulin (AREG) that were significantly down-regulated in the E group [PGR (−6.2 fold, p=0.000008) and AREG (−3.2 fold, p=.0006) but unchanged or up-regulated in the T group (PGR unchanged and AREG +9.2 fold p=0.00002). These findings were confirmed by RT-PCR.

Conclusions: Using the MCF7/AC1 model previously used to show the superiority of AI's over T, HDE demonstrated similar antitumor activity to L and was superior to T. In cells resistant to L, E was superior to T and gene expression changes demonstrate that E down-regulates while T activates estrogen regulated genes. These findings support the ongoing development of E for the treatment of ER+ BC.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD01-06.