Predictive and prognostic impact of TP53 mutations and MDM2 promoter genotype in primary breast cancer patients treated with epirubicin or paclitaxel.
ABSTRACT: TP53 mutations have been associated with resistance to anthracyclines but not to taxanes in breast cancer patients. The MDM2 promoter single nucleotide polymorphism (SNP) T309G increases MDM2 activity and may reduce wild-type p53 protein activity. Here, we explored the predictive and prognostic value of TP53 and CHEK2 mutation status together with MDM2 SNP309 genotype in stage III breast cancer patients receiving paclitaxel or epirubicin monotherapy.Each patient was randomly assigned to treatment with epirubicin 90 mg/m(2) (n?=?109) or paclitaxel 200 mg/m(2) (n?=?114) every 3rd week as monotherapy for 4-6 cycles. Patients obtaining a suboptimal response on first-line treatment requiring further chemotherapy received the opposite regimen. Time from last patient inclusion to follow-up censoring was 69 months. Each patient had snap-frozen tumor tissue specimens collected prior to commencing chemotherapy.While TP53 and CHEK2 mutations predicted resistance to epirubicin, MDM2 status did not. Neither TP53/CHEK2 mutations nor MDM2 status was associated with paclitaxel response. Remarkably, TP53 mutations (p?=?0.007) but also MDM2 309TG/GG genotype status (p?=?0.012) were associated with a poor disease-specific survival among patients having paclitaxel but not patients having epirubicin first-line. The effect of MDM2 status was observed among individuals harbouring wild-type TP53 (p?=?0.039) but not among individuals with TP53 mutated tumors (p>0.5).TP53 and CHEK2 mutations were associated with lack of response to epirubicin monotherapy. In contrast, TP53 mutations and MDM2 309G allele status conferred poor disease-specific survival among patients treated with primary paclitaxel but not epirubicin monotherapy.
Project description:INTRODUCTION: Mutations affecting p53 or its upstream activator Chk2 are associated with resistance to DNA-damaging chemotherapy in breast cancer. ATM (Ataxia Telangiectasia Mutated protein) is the key activator of p53 and Chk2 in response to genotoxic stress. Here, we sought to evaluate ATM's potential role in resistance to chemotherapy. METHODS: We sequenced ATM and assessed gene expression levels in pre-treatment biopsies from 71 locally advanced breast cancers treated in the neoadjuvant setting with doxorubicin monotherapy or mitomycin combined with 5-fluorouracil. Findings were confirmed in a separate patient cohort treated with epirubicin monotherapy. Each tumor was previously analyzed for CHEK2 and TP53 mutation status. RESULTS: While ATM mutations were not associated with chemo-resistance, low ATM expression levels predicted chemo-resistance among patients with tumors wild-type for TP53 and CHEK2 (P = 0.028). Analyzing the ATM-chk2-p53 cascade, low ATM levels (defined as the lower 5 to 50% percentiles) or mutations inactivating TP53 or CHEK2 robustly predicted anthracycline resistance (P-values varying between 0.001 and 0.027 depending on the percentile used to define "low" ATM levels). These results were confirmed in an independent cohort of 109 patients treated with epirubicin monotherapy. In contrast, ATM-levels were not suppressed in resistant tumors harboring TP53 or CHEK2 mutations (P > 0.5). CONCLUSIONS: Our data indicate loss of function of the ATM-Chk2-p53 cascade to be strongly associated with resistance to anthracycline/mitomycin-containing chemotherapy in breast cancer.
Project description:MDM2 plays a key role to physiological processes like growth arrest, senescence and apoptosis. It binds to and inhibits key proteins like p53 and the RB protein, and MDM2 amplification as well as protein overexpression without amplification is seen in many solid tumors. An MDM2 promoter polymorphism (SNP309T>G) has been found associated with enhanced Sp1 transcription factor binding and elevated MDM2 transcription. While 309G has been found associated with elevated cancer risk and young age at diagnosis of different cancers, results in Caucasians have been at variance. Recently, we reported a second polymorphism (SNP285G>C) located on the 309G allele. The 285C/309G haplotype accounts for about 12% of all 309G alleles among Norwegians, Dutch and British habitants. Assessing Sp1 binding to the MDM2 promoter using surface plasmon resonance technology, we found SNP309G to enhance Sp1 binding by 22% while SNP285C reduced Sp1 binding by 51%. SNP285C reduced the risk of breast cancer and ovarian cancer among 309TG/309GG carriers by 21 and 26%, respectively, but in particular the risk of ovarian cancer among 309TG heterozygotes (reduction by 37%). The fact that the 285C/309G haplotype accounted for only 1.9% of all 309G alleles among Finns and was absent in Chinese indicate 285C to be a young polymorphism.
Project description:The prevalence of germ line mutations in non-BRCA1/2 genes associated with hereditary breast cancer (BC) is low, and the role of some of these genes in BC predisposition and pathogenesis is conflicting. In this study, 5589 consecutive BC index patients negative for pathogenic BRCA1/2 mutations and 2189 female controls were screened for germ line mutations in eight cancer predisposition genes (ATM, CDH1, CHEK2, NBN, PALB2, RAD51C, RAD51D, and TP53). All patients met the inclusion criteria of the German Consortium for Hereditary Breast and Ovarian Cancer for germ line testing. The highest mutation prevalence was observed in the CHEK2 gene (2.5%), followed by ATM (1.5%) and PALB2 (1.2%). The mutation prevalence in each of the remaining genes was 0.3% or lower. Using Exome Aggregation Consortium control data, we confirm significant associations of heterozygous germ line mutations with BC for ATM (OR: 3.63, 95%CI: 2.67-4.94), CDH1 (OR: 17.04, 95%CI: 3.54-82), CHEK2 (OR: 2.93, 95%CI: 2.29-3.75), PALB2 (OR: 9.53, 95%CI: 6.25-14.51), and TP53 (OR: 7.30, 95%CI: 1.22-43.68). NBN germ line mutations were not significantly associated with BC risk (OR:1.39, 95%CI: 0.73-2.64). Due to their low mutation prevalence, the RAD51C and RAD51D genes require further investigation. Compared with control datasets, predicted damaging rare missense variants were significantly more prevalent in CHEK2 and TP53 in BC index patients. Compared with the overall sample, only TP53 mutation carriers show a significantly younger age at first BC diagnosis. We demonstrate a significant association of deleterious variants in the CHEK2, PALB2, and TP53 genes with bilateral BC. Both, ATM and CHEK2, were negatively associated with triple-negative breast cancer (TNBC) and estrogen receptor (ER)-negative tumor phenotypes. A particularly high CHEK2 mutation prevalence (5.2%) was observed in patients with human epidermal growth factor receptor 2 (HER2)-positive tumors.
Project description:Differentially expressed genes between BRCA1/BRCA2 negative and positive mutation driven-tumors. Screening for germline mutations was performed in a cohort of 55 patients under the age of 35 years in the BRCA1, BRCA2, CHEK2 (c.del1,100C) and TP53 genes, and the respective tumors were investigated regarding hormonal receptors status, HER2 expression. Transcriptional profiles were performed using Agilent one color hybridizations in a G4112F platform.
Project description:A functional polymorphism within MDM2, SNP309 T>G, has been linked to early onset cancer. This study examined clinical associations of breast cancer with SNP309 in a Scottish Caucasian population and investigated additional MDM2 intron 1 polymorphisms.Intron 1 of MDM2 was PCR amplified and directly sequenced from 299 breast cancer patients and 275 cancer free controls and compared with clinical and pathological parameters.SNP309 was observed, for the control and breast cancer cohorts respectively, at frequencies of: T/T = 44.7% and 39.5%; G/T = 42.2% and 47.2%; G/G = 13.1% and 13.4%, indicating that SNP309 is not a predisposing factor for breast cancer. The 309G/G genotype was associated with high grade tumours (OR = 1.64, 95%CI = 1.06-2.53, p = 0.025) and greater nodal involvement (OR = 2.51, 95%CI = 1.26-4.98, p = 0.009). SNP309 was not associated with an earlier age of cancer diagnosis. No association was observed between genotype and age of breast cancer diagnosis when patients were stratified by menopausal status and estrogen receptor status. Three additional low frequency SNPs were identified: 344T>A, 285G>C and 443G>T, the latter two novel. SNP285 was in complete linkage disequilibrium with SNP309 (D' = 1.0) with the minor alleles being in phase with each other. Moreover, the 285C/C, 309G/G double homozygous genotype was only observed in the breast cancer cohort.SNP309G/G is associated with poor prognostic breast cancer features in the Scottish population. Additionally, a novel SNP, SNP285, that is in linkage disequilibrium with SNP309, may also have a role in breast tumorigenesis.
Project description:The efficacy of ALK inhibitors in patients with ALK-mutant neuroblastoma is limited, highlighting the need to improve their effectiveness in these patients. To this end, we sought to develop a combination strategy to enhance the antitumor activity of ALK inhibitor monotherapy in human neuroblastoma cell lines and xenograft models expressing activated ALK. Herein, we report that combined inhibition of ALK and MDM2 induced a complementary set of anti-proliferative and pro-apoptotic proteins. Consequently, this combination treatment synergistically inhibited proliferation of TP53 wild-type neuroblastoma cells harboring ALK amplification or mutations in vitro, and resulted in complete and durable responses in neuroblastoma xenografts derived from these cells. We further demonstrate that concurrent inhibition of MDM2 and ALK was able to overcome ceritinib resistance conferred by MYCN upregulation in vitro and in vivo. Together, combined inhibition of ALK and MDM2 may provide an effective treatment for TP53 wild-type neuroblastoma with ALK aberrations.
Project description:BACKGROUND:CHEK2 has previously been excluded as a major cause of Li-Fraumeni syndrome (LFS). One particular CHEK2 germline mutation, c.1100delC, has been shown to be associated with elevated breast cancer risk. The prevalence of CHEK2*1100delC differs between populations and has been found to be relatively high in the Netherlands. The question remains nevertheless whether CHEK2 germline mutations contribute to the Li-Fraumeni phenotype. METHODS:We have screened 65 Dutch TP53-negative LFS/LFL candidate patients for CHEK2 germline mutations to determine their contribution to the LFS/LFL phenotype. RESULTS:We identified six index patients with a CHEK2 sequence variant, four with the c.1100delC variant and two sequence variants of unknown significance, p.Phe328Ser and c.1096-?_1629+?del. CONCLUSION:Our data show that CHEK2 is not a major LFS susceptibility gene in the Dutch population. However, CHEK2 might be a factor contributing to individual tumour development in TP53-negative cancer-prone families.
Project description:This trial was designed to compare the efficacy and safety between epirubicin (E) and carboplatin (C) in combination with paclitaxel (P) and trastuzumab (H) in neoadjuvant setting. In 13 Chinese cancer centers, 100 patients with HER2-positive, locally advanced breast cancer were 1:1 randomized to receive medication as follows: trastuzumab and paclitaxel weekly combined with carboplatin weekly for PCH group, or epirubicin every 3 weeks for PEH group. Patients were given 4 to 6 cycles of chemotherapy. The primary endpoint was pathologic complete response (pCR) rate, which was no significant difference in PCH and PEH regimen (39.1% vs. 48.8%; p=0.365). However, PEH regimen achieved higher pCR in luminal-B (HER2-poitive) subgroup (55.0% vs. 24.0%; p = 0.033), but not in ERBB2+ subgroup (42.9% vs. 57.1%; p = 0.355). PEH regimen showed a favorable efficacy in PIK3CA mutated subgroup (69.2% vs.23.5%, p=0.012). No significant difference was observed in the subgroup analysis of TP53 mutation status, PTEN expression, FCGR2A SNP and FCGR3A SNP. Both regimens as neoadjuvant chemotherapy achieve similar efficacy and safety. PEH might improve pCR rate, especially in the luminal-B subtype and PIK3CA mutation subtype. PEH is feasible and less likely to increase the incidence of acute cardiac events compared to PCH.
Project description:<h4>Background</h4>MDM2/MDMX proteins are frequently elevated in hormone receptor-positive (ER+) breast cancer. We sought to determine the antitumor efficacy of the combination of ALRN-6924, a dual inhibitor of MDM2/MDMX, with chemotherapy in ER+ breast cancer models.<h4>Methods</h4>Three hundred two cell lines representing multiple tumor types were screened to confirm the role of TP53 status in ALRN-6924 efficacy. ER+ breast cancer cell lines (MCF-7 and ZR-75-1) were used to investigate the antitumor efficacy of ALRN-6924 combination. In vitro cell proliferation, cell cycle, and apoptosis assays were performed. Xenograft tumor volumes were measured, and reverse-phase protein array (RPPA), immunohistochemistry (IHC), and TUNEL assay of tumor tissues were performed to evaluate the in vivo pharmacodynamic effects of ALRN-6924 with paclitaxel.<h4>Results</h4>ALRN-6924 was active in wild-type TP53 (WT-TP53) cancer cell lines, but not mutant TP53. On ER+ breast cancer cell lines, it was synergistic in vitro and had enhanced in vivo antitumor activity with both paclitaxel and eribulin. Flow cytometry revealed signs of mitotic crisis in all treatment groups; however, S phase was only decreased in MCF-7 single agent and combinatorial ALRN-6924 arms. RPPA and IHC demonstrated an increase in p21 expression in both combinatorial and single agent ALRN-6924 in vivo treatment groups. Apoptotic assays revealed a significantly enhanced in vivo apoptotic rate in ALRN-6924 combined with paclitaxel treatment arm compared to either single agent.<h4>Conclusion</h4>The significant synergy observed with ALRN-6924 in combination with chemotherapeutic agents supports further evaluation in patients with hormone receptor-positive breast cancer.