Candidate colorectal cancer predisposing gene variants in Chinese early-onset and familial cases

AIM: To investigate whether whole-exome sequencing may serve as an efficient method to identify known or novel colorectal cancer(CRC) predisposing genes in early-onset or familial CRC cases.METHODS: We performed whole-exome sequencing in 23 Chinese patients from 21 families with nonpolyposis CRC diagnosed at ≤ 40 years of age, or from multiple affected CRC families with at least 1 firstdegree relative diagnosed with CRC at ≤ 55 years of age.Genomic DNA from blood was enriched for exome sequences using the Sure Select Human All Exon Kit, version 2(Agilent Technologies) and sequencing was performed on an Illumina Hi Seq 2000 platform.Data were processed through an analytical pipeline to search for rare germline variants in known or novel CRC predisposing genes.RESULTS: In total, 32 germline variants in 23 genes were identified and confirmed by Sanger sequencing.In 6 of the 21 families(29%), we identified 7 mutations in 3 known CRC predisposing genes including MLH1(5 patients), MSH2(1 patient), and MUTYH(biallelic, 1 patient), five of which were reported as pathogenic.Inthe remaining 15 families, we identified 20 rare and novel potentially deleterious variants in 19 genes, six of which were truncating mutations.One previously unreported variant identified in a conserved region of EIF2AK4(p.Glu738_Asp739insA rgA rg) was found to represent a local Chinese variant, which was significantly enriched in our early-onset CRC patient cohort compared to a control cohort of 100 healthy Chinese individuals scored negative by colonoscopy(33.3% vs 7%, P 0.001).CONCLUSION: Whole-exome sequencing of early-onset or familial CRC cases serves as an efficient method to identify known and potential pathogenic variants in established and novel candidate CRC predisposing genes.     

Solitary fibrous tumour of the cheek: An unusual presentation of a rare soft tissue tumour

This case report discusses the unusual presentation and ultrasound features of a solitary fibrous tumour of the face. Solitary fibrous tumour is an uncommon form of soft tissue tumour which, although seen predominantly within the lung pleura, can occur throughout the body in sites such as the peritoneum, mediastinum and head and neck. Ultrasound is an excellent imaging modality in the assessment of soft tissue masses in the head and neck. The ultrasound features demonstrated by this example of solitary fibrous tumour are reviewed. This report also highlights that ultrasound alone is ultimately limited in reaching a definitive diagnosis. The roles of other investigations such as ultrasound-guided biopsy and cross-sectional imaging are discussed.     

Effects of recombinant human granulocyte-macrophage colony-stimulating factor on intracellular pH in mature granulocytes

We studied the effects of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSFrh) on the internal pH of granulocytes using the fluorescent probe BCECF. GM-CSFrh did not directly alter the resting pH of granulocytes isolated from the peripheral blood; however, when the cells were preincubated for 90 minutes with the growth factor and then activated with the chemotactic peptide N-formyl met leu phe (fMLP), they exhibited both an acceleration in the initial rate of acidification and a marked delay in realkalinization. The kinetic changes both in initial acidification and in subsequent realkalinization induced by GM-CSFrh priming were not prevented by protein synthesis inhibitors and were observed in granulocytes harvested from patients with both sex-linked and autosomal recessive chronic granulomatous disease (CGD). By directly quantitating H+ ion secretion, by monitoring the effects of sodium repletion on intracellular pH, and through use of the sodium channel inhibitors amiloride and dimethyl amiloride and the Na+/K+-ATPase inhibitor ouabain, we showed that the altered kinetics of intracellular acidification and alkalinization following fMLP stimulation of GM-CSFrh- primed granulocytes could not be accounted for by changes in transmembrane proton exportation regulated by the Na+/H+ antiport channel. Although the initial acidification following fMLP was abrogated by 2-deoxy-D-glucose in both GM-CSFrh-pretreated and GM-CSFrh- untreated granulocytes, retardation of the subsequent phase of alkalinization was observed in GM-CSFrh-primed cells even after inhibition of both glycolytic and mitochondrial metabolism. Our data indicate that the increased cytosolic acidification following fMLP stimulation in granulocytes "primed" with GM-CSFrh does not result from disordered proton excretion but instead from increased release of intracellular free acid which is only partially coupled to glucose catabolism or to the generation of superoxide anion (O2-).     

Estrogen Receptor Beta mRNA Expression in Normal and Adenomatous Pituitaries

Estrogen (E2), acting via its nuclear receptors, has been implicated in tumor development and growth, particularly in the pathogenesis of breast cancer. E2 also modulates anterior pituitary hormone production and is a potent cell mitogen. Until recently, the actions of E2 were thought to be mediated by a single estrogen receptor (ER) isoform (ER), and currently little is known of the pathophysiological relevance of the ER isoform. The presence of ER mRNA has been demonstrated by RT-PCR in the normal human pituitary, although expression of ER mRNA in human pituitary tumors has not been described. We have used semiquantitative RT-PCR to determine the relative levels of expression of ER mRNA in normal human pituitaries, non-functioning pituitary adenomas and GH-secreting tumors. ER mRNA was detected in normal pituitaries and all pituitary tumors examined. The ratio of ER mRNA to -actin mRNA expression was significantly reduced in non-functioning pituitary tumors (NFTs; 0.92 ± 0.09; mean ± SE; n=23) compared with findings in normal pituitaries (1.56 ± 0.21; mean ± SE; n=5; p<0.05 Student's t-test). Studies of ER protein expression are required to determine the functional significance of reduced ER mRNA expression in NFTs.     

The effect of PGI2 and theophylline on the response of platelets subjected to shear stress

A specially designed rotational viscometer was used to investigate the effects of the antiplatelet agent PGI2 in combination with theophylline on the response of human platelets subjected to shear stress. Samples of citrated platelet-rich plasma (PRP) were exposed to shear stress in the viscometer for a period of 5 min at 23 degrees C. The levels of stress studied ranged from 50 to 300 dynes/sq cm. Pretreatment of the platelets with 0.01 microM PGI2 and 500 microM theophylline before exposure to shear stress caused a large reduction in shear-induced platelet aggregation. However, it was also observed that the PGI2-- theophylline pretreatment concomitantly caused a large increase in shear-induced platelet lysis and serotonin release at stress levels equal to or greater than 150 dynes/sq cm. This observed increase in platelet fragility may have important implications for clinical applications of PGI2. The results are discussed and compared to those obtained in prior work in which platelets were pretreated with acetylsalicylic acid or with PGE1.