A Genetic Risk Score to Personalize Prostate Cancer Screening, Applied to Population Data

BACKGROUND

A polygenic hazard score (PHS), the weighted sum of 54 SNP genotypes, was previously validated for association with clinically significant prostate cancer and for improved prostate cancer screening accuracy. Here, we assess the potential impact of PHS-informed screening.

METHODS

United Kingdom population incidence data (Cancer Research United Kingdom) and data from the Cluster Randomized Trial of PSA Testing for Prostate Cancer were combined to estimate age-specific clinically significant prostate cancer incidence (Gleason score ≥7, stage T3-T4, PSA ≥10, or nodal/distant metastases). Using HRs estimated from the ProtecT prostate cancer trial, age-specific incidence rates were calculated for various PHS risk percentiles. Risk-equivalent age, when someone with a given PHS percentile has prostate cancer risk equivalent to an average 50-year-old man (50-year-standard risk), was derived from PHS and incidence data. Positive predictive value (PPV) of PSA testing for clinically significant prostate cancer was calculated using PHS-adjusted age groups.

RESULTS

The expected age at diagnosis of clinically significant prostate cancer differs by 19 years between the 1st and 99th PHS percentiles: men with PHS in the 1st and 99th percentiles reach the 50-year-standard risk level at ages 60 and 41, respectively. PPV of PSA was higher for men with higher PHS-adjusted age.

CONCLUSIONS

PHS provides individualized estimates of risk-equivalent age for clinically significant prostate cancer. Screening initiation could be adjusted by a man's PHS.

IMPACT

Personalized genetic risk assessments could inform prostate cancer screening decisions.

Macrophageal infiltration and microvessel density in laryngeal carcinoma: study of 52 cases

Angiogenesis is one of the six originally constituted hallmarks of cancer that has been extensively studied in the last two decades. The aim of our study is to assess the microvessel and macrophageal density in laryngeal carcinoma and its clinicopathological correlations. We immunohistochemically assessed microvessel density (CD34) and macrophage count (CD68) using microarray techniques and then looked for clinicopathological correlations. The mean micro-vessel density in the study group was 14.27 ± 12.92 vessels in a ×200 field with a mean macrophageal infiltration density of 5.19 ± 4.32. Median microvessel density was significantly higher in patients with metastasis than in patients without metastasis. Additionally, linear regression established that macrophageal infiltration density could predict microvessel density in laryngeal carcinoma. We found no association between either factor and recurrence rate or other clinical characteristics. Our study adds additional data to a problem that has been widely studied during the last two decades, even if controversies in this area still remain.

Genome-wide association study of prostate cancer-specific survival

BACKGROUND

Unnecessary intervention and overtreatment of indolent disease are common challenges in clinical management of prostate cancer. Improved tools to distinguish lethal from indolent disease are critical.

METHODS

We performed a genome-wide survival analysis of cause-specific death in 24,023 prostate cancer patients (3,513 disease-specific deaths) from the PRACTICAL and BPC3 consortia. Top findings were assessed for replication in a Norwegian cohort (CONOR).

RESULTS

We observed no significant association between genetic variants and prostate cancer survival.

CONCLUSIONS

Common genetic variants with large impact on prostate cancer survival were not observed in this study.

IMPACT

Future studies should be designed for identification of rare variants with large effect sizes or common variants with small effect sizes.

Mutational Status of CDKN2A and TP53 Genes in Laryngeal Squamous Cell Carcinoma

Laryngeal squamous cell carcinoma (LSCC) is the second most common tumour of the head and neck. It is characterized by frequent aberrations in two cell-cycle regulators--CDKN2A and TP53. However, LSCC has been often studied as a part of the group of head and neck cancers and not as an individual entity. In the current study we aimed to examine mutation status of CDKN2A and TP53 genes in 108 LSCC patients. DNA was extracted from fresh-frozen tumour tissues; exons 1-3 of CDKN2A and exons 5-8 of TP53 were screened for mutations by direct sequencing. Genetic aberrations in CDKN2A were found in 16 (14.2%) and those in TP53--in 56/108 (51.9%) tumours. Seven mutations (two insertions, three deletions, one missense and one silent) detected in CDKN2A were not described previously. Also, we found seven novel deletions and a novel indel in TP53. No significant associations with clinical features were found. However, TP53 mutations were predominantly observed in smokers with advanced stage tumours. Screening for genetic aberrations in a defined group of LSCC contributes to the knowledge about laryngeal carcinogenesis. Further investigations are required to confirm the observed trends in associations with clinical features.

Promoter hypermethylation of CDKN2A, MGMT, MLH1, and DAPK genes in laryngeal squamous cell carcinoma and their associations with clinical profiles of the patients

BACKGROUND

Laryngeal squamous cell carcinoma (laryngeal SCC) is a frequently occurring cancer of the head and neck area. Epigenetic changes of tumor-related genes contribute to its genesis and progression.

METHODS

We assessed promoter methylation status of the selected genes (CDKN2A, MGMT, MLH1, and DAPK) using methylation-sensitive high resolution melting (MS-HRM) in 100 patients with laryngeal SCC and studied the correlations with clinical characteristics.

RESULTS

The prevalence of promoter methylation in MGMT, CDKN2A, MLH1, and DAPK was 59 of 97 (60.8%), 46 of 97 (47.4%), 45 of 97 (46.4%), and 41 of 97 patients (42.3%), respectively. Significantly increased methylation of CDKN2A was observed in heavy smokers. Epigenetic inactivation of CDKN2A and MLH1 were found to be associated with lymph node involvement. An inverse correlation was present between MLH1 methylation and alcohol consumption.

CONCLUSION

Our results strongly suggest that deregulation of p16-associated, and MLH1-associated pathways, because of promoter hypermethylation, is associated with increased cancer cell migration, tumor invasiveness, and, thus, aggressive phenotype.

APC promoter 1B deletion in familial polyposis--implications for mutation-negative families

Over 1500 adenomatous polyposis coli (APC) gene mutations have already been identified as causative of familial adenomatous polyposis (FAP). However, routine genetic testing fails to detect mutations in about 10% of classic FAP cases. Recently, it has been shown that a proportion of mutation-negative FAP cases bear molecular changes in deep intronic and regulatory sequences. In this study, we used direct sequencing, followed by multiplex ligation-dependent probe amplification (MLPA) of genomic DNA from family members, affected by classic FAP. We first reported the family as mutation negative. With the launch of a new version of MLPA kit, we retested the family and a novel full deletion of promoter 1B was detected. The exact breakpoints of the deletion were determined by array comparative genomic hybridization (CGH) and long range polymerase chain reaction (PCR), followed by direct sequencing. The total APC expression levels were investigated by quantitative polymerase chain reaction (qPCR) assay and allele-specific expression (ASE) analysis. The APC gene expression was highly reduced, which indicates causative relationship. We suggest that there is a significant possibility that APC promoter 1B mutations could be found in mutation-negative FAP patients. In the light of our findings it seems reasonable to consider targeted genetic re-analysis of APC promoter 1B region in a larger cohort of unsolved cases.

No evidence of association between 118A>G OPRM1 polymorphism and heroin dependence in a large Bulgarian case-control sample

The μ-opioid receptor is the primary site of action of most opioids. The 118A>G (rs1799971) polymorphism in exon 1 of the μ-opioid receptor gene (OPRM1) leads to an Asn40Asp amino acid change that affects a putative N-glycosylation site. It has been widely investigated for association with alcohol and drug dependence and pain sensitivity, with mixed results. The aim of the current study was to examine whether this polymorphism was associated with heroin dependence in a large Bulgarian cohort of 1842 active users and 1451 population controls. SNP genotyping was done using Real-Time PCR TaqMan technology. Association analyses were conducted, separately for Roma and non-Roma participants. Our results suggest that there is no direct effect of 118A>G genotype on the risk for heroin dependence among active heroin users.

CK2 Is Acting Upstream of MEK3/6 as a Part of the Signal Control of ERK1/2 and p38 MAPK during Keratinocytes Autocrine Differentiation

Protein kinase CK2 (formerly termed “casein kinase II”) is a ubiquitously in mammalian cells distributed Ser/Thr kinase, with global role in cell regulation. Although, the involvement of CK2 in cell signalling is vast-investigated, virtually nothing is known about its contribution to signal control of keratinocytes differentiation. Here we show that, in autocrine differentiating keratinocytes, inhibition of the CK2 activity induced by 4,5,6,7-tetrabromobenzotriazole (TBB) causes reciprocal changes in the activities of major signal transduction regulators of keratinocytes differentiation, i.e. ERK1/2 and p38 MAPK, without affecting their protein levels. The ERK1/2 activity is strongly suppressed, while the activity of p38 is increased. We have also found that the activity of upstream and specifi c for p38 MAPK kinase MEK3/6 is also stimulated by TBB. These original results clearly demonstrate the participation of CK2 in the signal transduction pathway controlling MEK3/6, p38 MAPK, and ERK1/2 in the used model system.

CK2 is acting upstream of MEK3/6 as a part of the signal control of ERK1/2 and p38 MAPK during keratinocytes autocrine differentiation

Protein kinase CK2 (formerly termed "casein kinase II") is a ubiquitously in mammalian cells distributed Ser/Thr kinase, with global role in cell regulation. Although, the involvement of CK2 in cell signalling is vast-investigated, virtually nothing is known about its contribution to signal control of keratinocytes differentiation. Here we show that, in autocrine differentiating keratinocytes, inhibition of the CK2 activity induced by 4,5,6,7-tetrabromobenzotriazole (TBB) causes reciprocal changes in the activities of major signal transduction regulators of keratinocytes differentiation, i.e. ERK1/2 and p38 MAPK, without affecting their protein levels. The ERK1/2 activity is strongly suppressed, while the activity of p38 is increased. We have also found that the activity of upstream and specific for p38 MAPK kinase MEK3/6 is also stimulated by TBB. These original results clearly demonstrate the participation of CK2 in the signal transduction pathway controlling MEK3/6, p38 MAPK, and ERK1/2 in the used model system.

Vanadate-induced inhibition of BCR-triggered apoptosis is coupled with tyrosine phosphorylation and induction of G2M growth arrest in Ramos-BL B cells

The regulation of the tyrosine phosphorylation of key signaling molecules by tyrosine kinases and phosphatases is essential for BCR-triggered signaling cascades during B cell selection process. We used the non-selective tyrosine phosphatase inhibitor vanadate to study the importance of the late regulation of the tyrosine phosphorylation for BCR-triggered G1 growth arrest and apoptosis in Ramos-BL B cells. Vanadate induces G2M growth arrest in a dose-dependent manner and prevents BCR-triggered apoptosis. Vanadate-induced upregulation of the tyrosine phosphorylation is concomitant with increased expression of cyclin B and inhibition of caspase-3 activation and PARP cleavage. The anti-apoptotic effect of vanadate was observed even when added up to 6 hours after the treatment of Ramos-BL B cells with anti-IgM. Vanadate increases BCR-triggered tyrosine phosphorylation of the cytosolic tyrosine phosphatases, SHP-1 and SHP-2 after 24 hours. Co-stimulation with anti-CD40 prevents anti-IgM-triggered tyrosine phosphorylation of these phosphatases and up-regulates the expression of SHP-1. We conclude that the regulation of the tyrosine phosphatase activity is indispensable for BCR-triggered execution of the apoptosis in Ramos-BL B cells.

Frequency and application of the hot spot BRAF gene mutation (p.V600E) in the diagnostic strategy for Hereditary Nonpolyposis Colorectal Cancer

BACKGROUND

BRAF somatic mutations were reported with high frequency in sporadic colorectal cancers (CRCs) with microsatellite instability (MSI). The hot spot c. 1799 T>A, p.V600E gene mutation is very rarely involved in the tumorigenesis of CRC linked to Hereditary Nonpolyposis Colorectal Cancer (HNPCC). These data suggested that the screening of mismatch repair (MMR) genes could be avoided in cases positive for p.V600E. The aim of our study was to analyze the frequency of this hotspot mutation in a group of 140 CRC patients and the applicability of BRAF 15 exon mutation screening in the diagnosis of HNPCC.

METHODS

Exon 15 of the BRAF gene was PCR amplified and subjected to single-strand conformation polymorphism (SSCP) analysis. Samples showing an altered mobility pattern were then subjected to direct sequencing. Associations between BRAF mutation and clinical, pathological or molecular features were evaluated using Fisher's exact chi-squared tests as appropriate.

RESULTS

The mutation was detected in eight of 140 (5.7%) CRC samples with common characteristic features such as MSI, proximal tumor location, moderate differentiation, mucinous production and early Dukes' stage.

CONCLUSIONS

We conclude that screening for this mutation is an efficient tool in the diagnostic strategy for HNPCC.

Saponins from Tribulus terrestris L are less toxic for normal human fibroblasts than for many cancer lines: influence on apoptosis and proliferation

The objective of the study was to explore the influence of saponins derived from Tribulus terrestris L. (TT) on normal human skin fibroblasts and to compare it with their anticancer properties. In this study, [3H]thymidine incorporation and MTT to assess cell proliferation and viability, respectively, and immunoblotting and HPLC analysis to explore intracellular signal transduction pathways have been used. We found that TT caused a dose-dependent decrease in [3H]thymidine incorporation into the DNA of treated fibroblast compared to the untreated controls. Viability of treated cells remained within the control levels with treatment of up to 5 micro g TT/ml medium. It was significantly depressed with incubation in > or =6 micro g TT/ml medium with an IC50 of 12.6 micro g TT/ml of cultivating media. ERK1/2 was significantly dephosphorylated at 5 mins of incubation with TT until the 48th hour, when phosphorylation slightly recovered, but was still below the control levels. In contrast, p38 and JNK phosphorylation was positively influenced, with peaks at 1 hr and 24 hrs of incubation respectively. Phosphorylation/dephosphorylation events of SAPK/MAPK clearly correlated with Mkp-1 induction. Procaspase 3 was activated after 5 mins of incubation and coincided with a rapid actin cleavage. There was a significant decrease of putrescine concentration and a concomitant increase of spermidine and spermine at 2 mins of treatment. According to our results, TT is less toxic for normal human skin fibroblasts in comparison to many cancer lines investigated in previous studies. The molecular mechanism of this cytotoxicity involves up- and downregulation of polyamines' homeostasis, suppression of proliferation, and induction of apoptosis. Further research in this field using animal models would help to explore and interpret the potential properties of TT as an anticancer supplement.

Microsatellite instability in Bulgarian patients with endometrial cancer

PURPOSE

Microsatellite instability (MSI) is a frequent event in different types of cancer. In several studies MSI was shown to have both clinical and prognostic value. The aim of our study was to determine the frequency of MSI in Bulgarian patients with endometrial cancer (EC) and the possible relation of this phenomenon to their clinicopathological characteristics.

PATIENTS AND METHODS

A total of 33 histologically confirmed EC patients were analyzed for tumor MSI using a panel of 6 microsatellite markers.

RESULTS

We identified MSI in 30% of endometrial cancer cases. Six of them had high degree of MSI (MSI-H), and 4 displayed low degree of MSI (MSI-L).

CONCLUSION

The frequency of MSI in Bulgarian EC patients does not differ significantly from that reported in other European studies.

Regulation of tyrosine phosphorylation during the CD40-mediated rescue of Ramos-BL B cells from BCR-triggered apoptosis

The regulation of tyrosine phosphorylation is essential for BCR-triggered cellular responses during the selection process in the germinal centres. We were interested in examining the temporal regulation of tyrosine phosphorylation following CD40 cross-linking of anti-IgM-triggered Ramos-BL B cells. CD40 co-stimulation of anti-IgM-treated Ramos-BL B cells rescued them from growth inhibition and apoptosis, even when anti-CD40 Abs were added up to 12 h after the cross-linking of the BCR. The initial up-regulation of tyrosine phosphorylation triggered by BCR cross-linking is followed by tyrosine dephosphorylation after 12 h of stimulation, coinciding with pro-caspase-3 processing and PARP cleavage. We find that CD40 co-stimulation rescues BCR-triggered Ramos-BL B cells only before the irreversible inhibition of tyrosine kinase activity after 12 h of BCR cross-linking and that this is coupled with up-regulation of tyrosine phosphorylation; thus demonstrating the importance of the late regulation of tyrosine phosphorylation for CD40-mediated rescue of Ramos-BL B cells from BCR-triggered G1 growth arrest and apoptosis.

The aphrodisiac herb Tribulus terrestris does not influence the androgen production in young men

OBJECTIVE

The aim of the current study is to investigate the influence of Tribulus terrestris extract on androgen metabolism in young males.

DESIGN AND METHODS

Twenty-one healthy young 20-36 years old men with body weight ranging from 60 to 125 kg were randomly separated into three groups-two experimental (each n=7) and a control (placebo) one (n=7). The experimental groups were named TT1 and TT2 and the subjects were assigned to consume 20 and 10 mg/kg body weight per day of Tribulus terrestris extract, respectively, separated into three daily intakes for 4 weeks. Testosterone, androstenedione and luteinizing hormone levels in the serum were measured 24 h before supplementation (clear probe), and at 24, 72, 240, 408 and 576 h from the beginning of the supplementation.

RESULTS

There was no significant difference between Tribulus terrestris supplemented groups and controls in the serum testosterone (TT1 (mean+/-S.D.: 15.75+/-1.75 nmol/l); TT2 (mean+/-S.D.: 16.32+/-1.57 nmol/l); controls (mean+/-S.D.: 17.74+/-1.09 nmol/l) (p>0.05)), androstenedione (TT1 (mean+/-S.D.: 1.927+/-0.126 ng/ml); TT2 (mean+/-S.D.: 2.026+/-0.256 ng/ml); controls (mean+/-S.D.: 1.952+/-0.236 ng/ml) (p>0.05)) or luteinizing hormone (TT1 (mean+/-S.D.: 4.662+/-0.274U/l); TT2 (mean+/-S.D.: 4.103+/-0.869U/l); controls (mean+/-S.D.: 4.170+/-0.406U/l) (p>0.05)) levels. All results were within the normal range. The findings in the current study anticipate that Tribulus terrestris steroid saponins possess neither direct nor indirect androgen-increasing properties. The study will be extended in the clarifying the probable mode of action of Tribulus terrestris steroid saponins.

delta-Opioid agonist induced regulation of E2F1 DNA binding activity in NG108-15 cells

Activation of opioid receptors have been implicated in the modulation of cell proliferation and the E2F family of transcription factors may play a role in opioid inhibition of DNA synthesis. Gel shift assays and Western blotting of nuclear extracts from NG108-15 cells revealed increased E2F1 DNA binding activity and higher levels of E2F1 following activation of delta-opioid receptors. It is suggested that DADLE-induced regulation of E2F DNA binding activity involves ERKs.

Identification and purification of a novel serine/threonine messenger-independent growth-related protein kinase from lactating goat mammary gland

A second messenger-independent serine/threonine protein kinase from lactating goat mammary gland is purified and characterized. The purification steps include: homogenization, ultracentrifugation, ammonium sulphate precipitation, DEAE-Sepharose, phosphocellulose, hydrophobic and Mono Q columns. On the final step of purification the enzyme is revealed as a single band of mol wt 45,000 on silver-stained SDS-PAGE. Mg2+ and K+ are necessary for its optimum activity. Phosvitin and casein are substrates for the enzyme but kemptide, RRREEETEEE, protamine and histone mixture are all poorly phosphorylated. The kinase is inhibited by quercetin, heparin, random tyrosine- and glutamic acid-containing polymers, Ca2+, NaF, 2,3-bis-phosphoglycerate. 1 mM Mn2+ affects positively the basal level of the kinase activity but 5 mM Mn2+ completely suppress the effect of 10 mM Mg2+. Km of this enzyme for ATP is 1.57 microM and pH optimum is from 6 to 7. Isolation of this kinase is facilitated by its unusually high affinity for phosphocellulose.

The difference between cytosol and membrane growth-related protein kinase activities in lactating mouse mammary gland

1. A protein kinase activity which is cAMP-independent, inhibited by the bioflavonoid quercetin and probably connected to the growth of mammary gland cells was isolated and partially purified from cytosol. 2. Another protein kinase activity was demonstrated in crude membranes of lactating mouse mammary gland. 3. By the use of several different synthetic peptides as a substrate, it was demonstrated that the cytosol enzyme was a serine kinase, while the membrane protein kinase activity was mainly due to tyrosine kinase.

Insulin action in vivo on a growth-related protein kinase in lactating mouse mammary gland

1. A cytosol serine-protein kinase was isolated and partially purified from lactating mouse mammary gland which is cAMP-independent, inhibited by the bioflavonoid quercetin and probably connected to the growth of mammary cells. 2. After supra-physiological doses of insulin (0.4 IU daily) given in vivo the activity of this kinase rises 2.4 times, but at 5 times higher doses of insulin the activity was completely inhibited. 3. The biphasic effect of insulin suggests that this protein kinase might be connected to the growth effect of the hormone.