Skeletons in the p53 tumor suppressor closet: genetic evidence that p53 blocks bone differentiation and development

A series of in vitro tissue culture studies indicated that the p53 tumor suppressor promotes cellular differentiation, which could explain its role in preventing cancer. Quite surprisingly, however, two new in vivo studies (Lengner et al., 2006; Wang et al., 2006) provide genetic evidence that p53 blocks osteoblast differentiation and bone development. These interesting results and their biological and clinical implications are the focus of this comment

Research of non-specific hyperreactivity of upper airways in subjects with gastro-esophageal reflux (G.E.R.): Preliminary reports

An association between asthma and gastro-esophageal reflux (GER) is well recognized but the underlying mechanism is still unclear. The authors suggest that could exist an association between GER and upper airways hyperreactivity and this association could represents the mechanism underlying the lower esophageal sphincter releasing, that determine the reflux. In fact they suppose that, the noxious injury of acid reflux follows a course that could be: pharynx → larynx → bronchi → 1/3 inferior of the esophagus → reflux. From these presuppositions the authors carried out a study on the possible relationship between GER and non-specific hyperreactivity of upper airways on 14 subjects, divided in 2 groups: 10 subjects with functional GER, 4 subjects suffering from GER caused by hiatus hernia as control group. All patients had a thorough medical history, ENT examination with rigid and flexible endoscope, anterior Rhinomanometry (RRM), skin-test for inhalant and alimentary allergens, RAST, audiometric exam, non-specific nasal provocation test (NSNPT) with histamine, using as control the number of sneezes. From a through analysis of objective examination and from the results of the NSNPT with histamine resulted that all subjects with functional GER were rhinopathics. In all tests both in vivo (Skin-test) and in vitro (RAST) for the most common allergens (pollens-inhalant-mycophites-alimentary) the results were negative. The authors also found an involvement of paranasal sinuses that raised: 91% in the patients with recurrents phlogosis due to non specific nasal hyperreactivity; 40.9% in the allergic subjects (20% in the Graminacee +; 32% in the Parietaria O. +; 76% in the Dermatophagoides Pt. +; others 4%); 100% in the ASA-intollerance subjects. The NSNSPT with histamine showed in the group with functional GER a hyperreactivity with sneezes in 6/10 subjects, and 1/4 subjects of the group with GER with hiatus hernia. The RRM variations showed an unilateral nasal hyperreactivity in 6/10, bilateral in 3/10 subjects of the group with functional GER. In the group with GER with hiatus hernia only 1/4 subject showed reliable unilateral RRM variation. From the analysis of data resulted that subjects with functional GER showed a completely involvement of the upper airways and not only of the pharynx and larynx, caused by non specific hyperreactivity at the NSNPT with histamine, associated with a chronic pathology

Proliferation and estrogen signaling can distinguish patients at risk for early versus late relapse among estrogen receptor positive breast cancers

Introduction: We examined if a combination of proliferation markers and estrogen receptor (ER) activity could predict early versus late relapses in ER-positive breast cancer and inform the choice and length of adjuvant endocrine therapy. Methods: Baseline affymetrix gene-expression profiles from ER-positive patients who received no systemic therapy (n = 559), adjuvant tamoxifen for 5 years (cohort-1: n = 683, cohort-2: n = 282) and from 58 patients treated with neoadjuvant letrozole for 3 months (gene-expression available at baseline, 14 and 90 days) were analyzed. A proliferation score based on the expression of mitotic kinases (MKS) and an ER-related score (ERS) adopted from Oncotype DX® were calculated. The same analysis was performed using the Genomic Grade Index as proliferation marker and the luminal gene score from the PAM50 classifier as measure of estrogen-related genes. Median values were used to define low and high marker groups and four combinations were created. Relapses were grouped into time cohorts of 0-2.5, 0-5, 5-10 years. Results: In the overall 10 years period, the proportional hazards assumption was violated for several biomarker groups indicating time-dependent effects. In tamoxifen-treated patients Low-MKS/Low-ERS cancers had continuously increasing risk of relapse that was higher after 5 years than Low-MKS/High-ERS cancers [0 to 10 year, HR 3.36; p = 0.013]. High-MKS/High-ERS cancers had low risk of early relapse [0-2.5 years HR 0.13; p = 0.0006], but high risk of late relapse which was higher than in the High-MKS/Low-ERS group [after 5 years HR 3.86; p = 0.007]. The High-MKS/Low-ERS subset had most of the early relapses [0 to 2.5 years, HR 6.53; p < 0.0001] especially in node negative tumors and showed minimal response to neoadjuvant letrozole. These findings were qualitatively confirmed in a smaller independent cohort of tamoxifen-treated patients. Using different biomarkers provided similar results. Conclusions: Early relapses are highest in highly proliferative/low-ERS cancers, in particular in node negative tumors. Relapses occurring after 5 years of adjuvant tamoxifen are highest among the highly-proliferative/high-ERS tumors although their risk of recurrence is modest in the first 5 years on tamoxifen. These tumors could be the best candidates for extended endocrine therapy

Association of the germline TP53 R337H mutation with breast cancer in southern Brazil

<p>Abstract</p> <p>Background</p> <p>The germline <it>TP53</it>-R337H mutation is strongly associated with pediatric adrenocortical tumors (ACT) in southern Brazil; it has low penetrance and limited tissue specificity in most families and therefore is not associated with Li-Fraumeni syndrome. However, other tumor types, mainly breast cancer, have been observed in carriers of several unrelated kindreds, raising the possibility that the R337H mutation may also contribute to breast tumorigenesis in a genetic background-specific context.</p> <p>Methods</p> <p>We conducted a case-control study to determine the prevalence of the R337H mutation by sequencing <it>TP</it>53 exon 10 in 123 women with breast cancer and 223 age- and sex-matched control subjects from southern Brazil. Fisher's test was used to compare the prevalence of the R337H.</p> <p>Results</p> <p>The R337H mutation was found in three patients but in none of the controls (p = 0.0442). Among the carriers, two had familial history of cancer meeting the Li-Fraumeni-like criteria. Remarkably, tumors in each of these three cases underwent loss of heterozygosity by eliminating the mutant <it>TP53 </it>allele rather than the wild-type allele. Polymorphisms were identified within the <it>TP53 </it>(R72P and Ins16) and <it>MDM2 </it>(SNP309) genes that may further diminish <it>TP53 </it>tumor suppressor activity.</p> <p>Conclusion</p> <p>These results demonstrate that the R337H mutation can significantly increase the risk of breast cancer in carriers, which likely depends on additional cooperating genetic factors. These findings are also important for understanding how low-penetrant mutant <it>TP53 </it>alleles can differentially influence tumor susceptibility.</p

Distinct pathways in the over-expression of matrix metalloproteinases in human fibroblasts by relaxation of mechanical tension.

peer reviewedaudience: researcherThe aim of the work was to analyze, on a comparative basis, the signaling pathways operating in the regulation of a panel of matrix metalloproteinases (MMP) expressed by human dermal fibroblasts submitted to mechanical stress relaxation by cytochalasin D (CD) and in a retracting collagen gel (RCG). The mRNA steady-state level of MMPs was measured by a quantitative RT-PCR procedure using a synthetic RNA as internal standard. In monolayer, most MMPs were barely detected, except MMP-2. Disruption of the actin stress fibers by CD induced a moderate increase of MMP-2 mRNA and a much larger stimulation of MMP-3, -9, -13 and -14 mRNAs. In RCG, a significant up-regulation of these MMPs was also observed although to a lower extent than in CD-treated monolayers. Among the investigated MMPs, the MMP-8 and -11 were not reproducibly detected. MMP-2 was processed to its active form both by CD and in RCG. The CD-induced up-regulation of gene expression was largely repressed by blocking protein synthesis by cycloheximide for all the MMPs, by inhibiting the tyrosine-kinases of the src family by herbimycin A for all MMPs, except MMP-2, and by inhibiting the TPA-inducible PKC isoforms by bisindoyl maleimide for all MMPs, except MMP-14. The up-regulation induced by stress relaxation in RCG was protein synthesis-dependent for MMP-2 and MMP-13, tyrosine kinases-dependent for MMP-3 and MMP-13, as previously described for MMP-1. Inhibiting TPA-inducible PKC did not affect any MMP in RCG except MMP-13, which was strongly induced. The processing of MMP-2 was tyrosine kinases-dependent but PKC-independent. Inhibitors of the ERK1,2 and p38 MAP kinases pathways diversely affected the MMPs expression. Inhibiting the Rho-kinase activity by Y-27632 was inactive. These results point to the potent regulation operated by the status of the cytoskeleton on the cell phenotype, and to distinct regulatory pathways involved in the control of different MMPs expression

Docetaxel vs 5-fluorouracil plus vinorelbine in metastatic breast cancer after anthracycline therapy failure

This multicentre, randomised phase III study compared docetaxel with 5-fluorouracil+vinorelbine in patients with metastatic breast cancer after failure of neo/adjuvant or one line of palliative anthracycline-based chemotherapy. One hundred and seventy-six metastatic breast cancer patients were randomised to receive docetaxel (100 mg m−2) every 3 weeks or 5-fluorouracil+vinorelbine: 5-fluorouracil (750 mg m−2 per day continuous infusion) D1–5 plus vinorelbine (25 mg m−2) D1 and D5 of each 3-week cycle. Eighty-six patients received 516 cycles of docetaxel; 90 patients received 476 cycles of 5-fluorouracil+vinorelbine. Median time to progression (6.5 vs 5.1 months) and overall survival (16.0 vs 15.0 months) did not differ significantly between the docetaxel and 5-fluorouracil+vinorelbine arms, respectively. Six (7%) complete responses and 31 (36%) partial responses occurred with docetaxel (overall response rate 43%, 95% confidence interval: 32–53%), while 4 (4.4%) complete responses and 31 (34.4%) partial responses occurred with 5-fluorouracil+vinorelbine (overall response rate 38.8%, 95% confidence interval: 29–49%). Main grade 3–4 toxicities were (docetaxel vs 5-fluorouracil+vinorelbine): neutropenia 82% vs 67%; stomatitis 5% vs 40%; febrile neutropenia 13% vs 22%; and infection 2% vs 7%. There was one possible treatment-related death in the docetaxel arm and five with 5-fluorouracil+vinorelbine. In anthracycline-pretreated metastatic breast cancer patients, docetaxel showed comparable efficacy to 5-fluorouracil+vinorelbine, but was less toxic

Inherited germline TP53 mutation encodes a protein with an aberrant C-terminal motif in a case of pediatric adrenocortical tumor

Childhood adrenocortical tumor (ACT), a very rare malignancy, has an annual worldwide incidence of about 0.3 per million children younger than 15 years. The association between inherited germline mutations of the TP53 gene and an increased predisposition to ACT was described in the context of the Li-Fraumeni syndrome. In fact, about two-thirds of children with ACT have a TP53 mutation. However, less than 10% of pediatric ACT cases occur in Li-Fraumeni syndrome, suggesting that inherited low-penetrance TP53 mutations play an important role in pediatric adrenal cortex tumorigenesis. We identified a novel inherited germline TP53 mutation affecting the acceptor splice site at intron 10 in a child with an ACT and no family history of cancer. The lack of family history of cancer and previous information about the carcinogenic potential of the mutation led us to further characterize it. Bioinformatics analysis showed that the non-natural and highly hydrophobic C-terminal segment of the frame-shifted mutant p53 protein may disrupt its tumor suppressor function by causing misfolding and aggregation. Our findings highlight the clinical and genetic counseling dilemmas that arise when an inherited TP53 mutation is found in a child with ACT without relatives with Li-Fraumeni-component tumors