Lactase persistence and bitter taste response: instrumental variables and mendelian randomization in epidemiologic studies of dietary factors and cancer risk

Consumption of dairy products seems to increase the risk of cancer at several sites, while intake of cruciferous vegetables could have protective effects. However, these dietary intakes are subject to measurement error, and associations with cancer could be due to confounders. Mendelian randomization has been suggested as a way to overcome confounding by exploiting the random allocation of alleles from parents to offspring. In mid-2006, the authors conducted a study of allele frequencies for the lactase (LCT) and taste receptor, type 2, member 38 (TAS2R38) genes, including 634 volunteers recruited (1992-1998) from the Italian branch of the European Prospective Investigation into Cancer and Nutrition. The authors hypothesized that there would be a lower milk intake among carriers of the LCT CC genotype and a different intake of cruciferous vegetables among carriers of the TAS2R38 variant. Overall, the frequency of the LCT T allele was higher in northern Italy than in southern Italy. Food intake was associated with gene variants. An association was evident for ice cream and LCT variants (p = 0.004); less so for milk intake. In addition, the TAS2R38 variant showed a geographic gradient and an association with cruciferous vegetable intake. These results suggest that the LCT and TAS2R38 variants are good candidates for Mendelian randomization studies of cancer and other health outcomes.     

FOLFOXIRI-Bevacizumab or FOLFOX-Panitumumab in Patients with Left-Sided RAS/BRAF Wild-Type Metastatic Colorectal Cancer: A Propensity Score-Based Analysis

BackgroundDoublets plus anti‐epidermal growth factor receptors (EGFRs) are the preferred upfront option for patients with left‐sided RAS/BRAF wild‐type metastatic colorectal cancer (mCRC). Initial therapy with FOLFOXIRI‐bevacizumab is superior to doublets plus bevacizumab independently from primary tumor sidedness and RAS/BRAF status. No randomized comparison between FOLFOXIRI‐bevacizumab versus doublets plus anti‐EGFRs is available in left‐sided RAS/BRAF wild‐type mCRC.Materials and MethodsWe selected patients with left‐sided RAS and BRAF wild‐type mCRC treated with first‐line FOLFOX‐panitumumab or FOLFOXIRI‐bevacizumab in five randomized trials: Valentino, TRIBE, TRIBE2, STEAM, and CHARTA. A propensity score‐based analysis was performed to compare FOLFOXIRI‐bevacizumab with FOLFOX‐panitumumab.ResultsA total of 185 patients received FOLFOX‐panitumumab and 132 received FOLFOXIRI‐bevacizumab. Median progression‐free survival (PFS) and median overall survival (OS) were 13.3 and 33.1 months in the FOLFOXIRI‐bevacizumab group compared with 11.4 and 30.3 months in the FOLFOX‐panitumumab group (propensity score‐adjusted hazard ratio (HR) for PFS, 0.82; 95% confidence interval (CI), 0.64–1.04; p = .11; propensity score‐adjusted HR for OS, 0.80; 95% CI, 0.59–1.08; p = .14). No significant differences in overall response rate and disease control rate were observed. A statistically nonsignificant difference in favor of FOLFOXIRI‐bevacizumab was observed for OS after secondary resection of metastases. Chemotherapy‐related adverse events were more frequent in the FOLFOXIRI‐bevacizumab group, with specific regard to grade 3 and 4 neutropenia (48% vs. 26%, adjusted p = .001).ConclusionAlthough randomized comparison is lacking, both FOLFOXIRI‐bevacizumab and FOLFOX‐panitumumab are valuable treatment options in left‐sided RAS/BRAF wild‐type mCRC.Implications for PracticeA propensity score‐based analysis of five trials was performed to compare FOLFOX‐panitumumab versus FOLFOXIRI‐bevacizumab in left‐sided RAS/BRAF wild‐type metastatic colorectal cancer (mCRC). No significant differences were observed, but FOLFOXIRI‐bevacizumab achieved numerically superior survival outcomes versus FOLFOX‐panitumumab. Chemotherapy‐related adverse events were more frequent in the FOLFOXIRI‐bevacizumab group. These observations suggest that although doublet chemotherapy plus anti‐EGFRs remains the preferred treatment in patients with left‐sided RAS/BRAF wild‐type mCRC, FOLFOXIRI‐bevacizumab is a valuable option able to provide similar, if not better, outcomes at the price of a moderate increase in toxicity and may be adopted based on patients’ preference and potential impact on quality of life.     

Role of NRAS mutations as prognostic and predictive markers in metastatic colorectal cancer

NRAS mutations occur in 3–5% of colorectal cancer. Differently from KRAS and BRAF mutations, the role of NRAS mutations as prognostic and predictive markers in metastatic colorectal cancer (mCRC) has been investigated to a lesser extent. A retrospective series suggested the role of NRAS mutations as predictors of resistance to anti‐EGFR monoclonal antibodies (MoAbs) in chemo‐refractory patients with mCRC. In our study, KRAS codons 12, 13, 61 and BRAF codon 600 mutational status were evaluated in mCRCs referred to our Institution from 2009 to 2012. NRAS codons 12, 13 and 61 mutational status was analyzed in KRAS/BRAF wt patients. We collected pathological and clinical features in the overall population and outcome data in a subset of NRAS mutated chemo‐refractory patients treated with anti‐EGFR MoAbs in advanced lines. NRAS was mutated in 47/786 (6%) mCRCs. NRAS and KRAS mutated tumors did not show significant differences in terms of clinical and pathological characteristics, except for a lower prevalence of mucinous histology (p = 0.012) and lung metastases (p = 0.012) among NRAS mutated tumors. In the uni‐ and multivariate model, NRAS mutations were associated with shorter overall survival (OS) compared to all wt patients (median OS 25.6 vs 42.7 months; univ: HR = 1.91, 95% CI 1.39–3.86, p = 0.0013; multiv: HR = 1.75, 95% CI 1.1.3–2.72, p = 0.013). None of the chemo‐refractory NRAS mutated patients evaluable for response to anti‐EGFRs achieved response. In conclusion, NRAS mutations have a relevant incidence in patients with mCRC and showed an association with specific clinical and pathological features. NRAS mutations affect mCRC patients' prognosis and predict lack of response to anti‐EGFRs.     

Intravital imaging reveals p53-dependent cancer cell death induced by phototherapy via calcium signaling

One challenge in biology is signal transduction monitoring in a physiological context. Intravital imaging techniques are revolutionizing our understanding of tumor and host cell behaviors in the tumor environment. However, these deep tissue imaging techniques have not yet been adopted to investigate the second messenger calcium (Ca²⁺). In the present study, we established conditions that allow the in vivo detection of Ca²⁺ signaling in three-dimensional tumor masses in mouse models. By combining intravital imaging and a skinfold chamber technique, we determined the ability of photodynamic cancer therapy to induce an increase in intracellular Ca²⁺ concentrations and, consequently, an increase in cell death in a p53-dependent pathway.     

A novel anti-GD2/4-1BB chimeric antigen receptor triggers neuroblastoma cell killing

Chimeric antigen receptor (CAR)-expressing T cells are a promising therapeutic option for patients with cancer. We developed a new CAR directed against the disialoganglioside GD2, a surface molecule expressed in neuroblastoma and in other neuroectoderm-derived neoplasms. The anti-GD2 single-chain variable fragment (scFv) derived from a murine antibody of IgM class was linked, via a human CD8α hinge-transmembrane domain, to the signaling domains of the costimulatory molecules 4-1BB (CD137) and CD3-ζ. The receptor was expressed in T lymphocytes by retroviral transduction and anti-tumor activities were assessed by targeting GD2-positive neuroblastoma cells using in vitro cytotoxicity assays and a xenograft model. Transduced T cells expressed high levels of anti-GD2 CAR and exerted a robust and specific anti-tumor activity in 4- and 48-hour cultures with neuroblastoma cells. Cytotoxicity was associated with the release of pro-apoptotic molecules such as TRAIL and IFN-γ. These results were confirmed in a xenograft model, where anti-GD2 CAR T cells infiltrating tumors and persisting into blood circulation induced massive apoptosis of neuroblastoma cells and completely abrogated tumor growth. This anti-GD2 CAR represents a powerful new tool to redirect T cells against GD2. The preclinical results of this study warrant clinical testing of this approach in neuroblastoma and other GD2-positive malignancies.     

Association between total number of deaths, diabetes mellitus, incident cancers, and haplotypes in chromosomal region 8q24 in a prospective study

The 8q24 region is a gene desert, although chromosomal aberrations and somatic amplification involving this region, including translocations involving the protooncogene c-MYC, have been frequently reported in people with cancer. To investigate the role of variants in 8q24 region, the authors analyzed data from a prospective study (n = 10,372 participants who were followed for 11 years) in which a large number of health events (>1,500) occurred (1993-1998). They genotyped all subjects for 5 candidate single nucleotide polymorphisms (rs672888, rs1447295, rs9642880, rs16901979, and rs6983267) that were identified in previous genome-wide scans. Although significant associations with individual single nucleotide polymorphisms were small in magnitude, the authors observed higher increases in the risks of different types of cancer with specific haplotypes, particularly when subjects were homozygous for the haplotype: for breast cancer and homozygotes for haplotype CAGCT, hazard ratio = 3.40, 95% confidence interval: 1.24, 9.21; for prostate cancer and grouped rare haplotypes, hazard ratio = 7.43, 95% confidence interval: 3.00, 18.37; and for brain cancer and homozygotes for haplotype CGGCT, hazard ratio = 13.48, 95% confidence interval: 3.00, 59.53. Significant associations were also observed between haplotypes and deaths from cardiovascular diseases and cerebrovascular diseases; the most stable association was between homozygotes for haplotypes CGTCG and CAGCT and total deaths in men (hazard ratio = 3.5, 95% confidence interval: 1.8, 6.9, and hazard ratio = 2.8, 95% confidence interval: 1.3, 6.4, respectively). In conclusion, the authors have observed a strong pleiotropic effect of the 8q24 region in a large prospective study. This observation can shed light on the mechanisms underlying reported associations between 8q24 variants and disparate chronic diseases.     

Erythropoietin: Novel Approaches to Neuroprotection in Human Brain Disease

With the increased life expectancy in western industrialized countries, the incidence and prevalence of brain diseases dramatically increased. Stroke and a wide spectrum of neuropsychiatric illnesses such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, traumatic head injury, and schizophrenia all lead to severe disability. However, targeted effective therapies for treatment of these diseases are lacking. Even more frustrating is the fact that we do not yet clearly understand the basic mechanisms underlying the disease processes in these conditions. We propose a hypothesis of loss of neuronal function via a final common deleterious pathway in this clinically very heterogeneous disease group. This review presents a novel neuroprotective concept for treatment of brain disease: Erythropoietin (EPO). EPO is a natural body-own-protein hormone that has been used for treatment of anemia for more than a decade. The neuroprotective approach using EPO in brain disease represents a totally new frontier. The “Göttingen EPO-stroke trial” represents the first effective use in man of a neuroprotective therapy in an acute brain disease while the experimental EPO therapy to combat cognitive decline in patients with schizophrenia will be introduced as an example of a neuroprotective strategy for a chronic brain disease.     

The endocrine response to ghrelin as a function of gender in humans in young and elderly subjects

Ghrelin modulates somatotroph, lactotroph, corticotroph, and insulin secretion and glucose metabolism. To clarify the influence of gender and age on the endocrine actions of ghrelin in humans, we studied the effects of ghrelin (1.0 micro g/kg iv) or placebo on GH, prolactin (PRL), ACTH, cortisol, insulin, glucagon, and glucose levels in 18 young subjects (YS) and 16 elderly subjects (ES) of both genders. The GH response to GHRH (1.0 micro g/kg iv) was also studied. The GH response to ghrelin in YS was higher (P < 0.01) than in ES and both higher (P < 0.01) than to GHRH, without gender-related differences. In YS ghrelin also induced: 1) gender-independent increase (P < 0.01) in PRL, ACTH, and cortisol levels; 2) gender-independent increase in glucose levels (P < 0.01); 3) decrease (P < 0.01) in insulin levels in male YS; and 4) no change in glucagon. In ES, ghrelin induced gender-independent PRL, ACTH, and cortisol responses (P < 0.01). In ES ghrelin elicited gender-independent transient decrease in insulin (P < 0.01) coupled with increase in glucose levels (P < 0.05). In conclusion, the GH-releasing effect of ghrelin is independent of gender but undergoes age-related decrease. The effect of ghrelin on lactotroph and corticotroph secretion is age and gender independent. In both ES and YS, ghrelin influences insulin secretion and glucose metabolism.     

Randomized controlled trial: effect of nutritional counselling in general practice

OBJECTIVES: To investigate the effectiveness of a non-structured 15-min educational intervention by general practitioners (GPs) on modifications of daily diet among healthy adults. DESIGN: Two arms randomized trial lasting 12 months. SETTING: Italian general practitioner wards. Subjects A total of 3,186 men and women aged 18-65 years recruited in the medical ward by their GPs. INTERVENTIONS: An educational intervention and a brochure on the basics of a healthy diet based on the Italian Guidelines for a Correct Nutrition, 1998. The main study goal was to attain an intake of fruits and vegetables >5 servings per day. Follow-up visit every 6 months. Main outcome measures Weight, blood pressure, and a 40-items Food Frequency Questionnaire. RESULTS: The intervention group showed a slightly reduced net intake of meat and a slightly increased net intake of fruits and vegetables, fish products, and olive oil. Body mass index (BMI) changed only in the treatment arm [-0.41 95% confidence interval (95% CI) -0.11 to -0.53]. The net change at 1 year in the intervention arm was +1.31 (CI 0.90-4.39) for fruits and vegetables, and -0.22 (-0.11 to -0.69) for meat (portions per week). We also computed a 'healthy diet score' reflecting compliance with recommended dietary habits. In the intervention group, the mean score at recruitment was significantly lower than the mean score at the end of follow-up (Crude score change = 0.29; CI 0.19-0.48). No differences were observed in the control group (Crude score change = -0.04; CI -0.22-0.02). The difference in score from baseline to the final visit, comparing the intervention vs the control group, was statistically significant (P < 0.001) (MANOVA adjusted by sex, BMI, education, and time). CONCLUSIONS: A brief educational intervention by GPs can induce multiple diet changes that may lower BMI and potentially reduce chronic disease risk in generally healthy adults.