36 research outputs found

    Clinical cyp2d6 genotyping to personalize adjuvant tamoxifen treatment in er-positive breast cancer patients: Current status of a controversy

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    Tamoxifen is a major option for adjuvant endocrine treatment in estrogen receptor (ER) positive breast cancer patients. The conversion of the prodrug tamoxifen into the most active metabolite endoxifen is mainly catalyzed by the enzyme cytochrome P450 2D6 (CYP2D6). Genetic variation in the CYP2D6 gene leads to altered enzyme activity, which influences endoxifen formation and thereby potentially therapy outcome. The association between genetically compromised CYP2D6 activity and low endoxifen plasma concentrations is generally accepted, and it was shown that tamoxifen dose increments in compromised patients resulted in higher endoxifen concentrations. However, the correlation between CYP2D6 genotype and clinical outcome is still under debate. This has led to genotype-based tamoxifen dosing recommendations by the Clinical Pharmacogenetic Implementation Consortium (CPIC) in 2018, whereas in 2019, the European Society of Medical Oncology (ESMO) discouraged the use of CYP2D6 genotyping in clinical practice for tamoxifen therapy. This paper describes the latest developments on CYP2D6 genotyping in relation to endoxifen plasma concentrations and tamoxifen-related clinical outcome. Therefore, we focused on Pharmacogenetic publications from 2018 (CPIC publication) to 2021 in order to shed a light on the current status of this debate

    ANKRd44 gene silencing: a putative role in trastuzumab resistance in HER2-like breast cancer

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    Trastuzumab is an effective therapeutic treatment for Her2-like breast cancer; despite this most of these tumors develop resistance to therapy due to specific gene mutations or alterations in gene expression. Understanding the mechanisms of resistance to Trastuzumab could be a useful tool in order to identify combinations of drugs that elude resistance and allow a better response for the treated patients. Twelve primary biopsies of Her2+/hormone receptor negative (ER-/PgR-) breast cancer patients were selected based on the specific response to neoadjuvant therapy with Trastuzumab and their whole exome was sequenced leading to the identification of 18 informative gene mutations that discriminate patients selectively based on response to treatment. Among these genes, we focused on the study of the ANKRD44 gene to understand its role in the mechanism of resistance to Trastuzumab. The ANKRD44 gene was silenced in Her2-like breast cancer cell line (BT474), obtaining a partially Trastuzumab-resistant breast cancer cell line that constitutively activates the NF-kb protein via the TAK1/AKT pathway. Following this activation an increase in the level of glycolysis in resistant cells is promoted, also confirmed by the up-regulation of the LDHB protein and by an increased TROP2 protein expression, found generally associated with aggressive tumors. These results allow us to consider the ANKRD44 gene as a potential gene involved in Trastuzumab resistance

    Identification of a targetable KRAS-mutant epithelial population in non-small cell lung cancer

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    Lung cancer is the leading cause of cancer deaths. Tumor heterogeneity, which hampers development of targeted therapies, was herein deconvoluted via single cell RNA sequencingin aggressive human adenocarcinomas (carrying Kras-mutations) and comparable murine model. We identified a tumor-specific, mutant-KRAS-associated subpopulation which is conserved in both human and murine lung cancer. We previously reported a key role for the oncogene BMI-1 in adenocarcinomas. We therefore investigated the effects of in vivo PTC596 treatment, which affects BMI-1 activity, in our murine model. Post-treatment, MRI analysis showed decreased tumor size, while single cell transcriptomics concomitantly detected near complete ablation of the mutant-KRAS-associated subpopulation, signifying the presence of a pharmacologically targetable, tumor-associated subpopulation. Our findings therefore hold promise for the development of a targeted therapy for KRAS-mutant adenocarcinomas

    A state observer for the Virgo inverted pendulum

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    International audienceWe report an application of Kalman filtering to the inverted pendulum (IP) of the Virgo gravitational wave interferometer. Using subspace method system identification techniques, we calculated a linear mechanical model of Virgo IP from experimental transfer functions. We then developed a Kalman filter, based on the obtained state space representation, that estimates from open loop time domain data, the state variables of the system. This allows the observation (and eventually control) of every resonance mode of the IP mechanical structure independently

    Monitoring of secondary drug resistance mutations in circulating tumor DNA of patients with advanced ALK positive NSCLC

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    Background Disease progression in ALK positive NSCLC patients treated with crizotinib occurs after a median of 9–10 months of treatment. Several mechanisms of resistance were identified and include ALK gene mutations and amplification and activation of bypassing signaling pathways like EGFR, KRAS or c-KIT. Second-generation ALK-TKIs demonstrated an enhanced spectrum of activity in crizotinib-resistant patients. However, re-biopsy in NSCLC patients represents a critical issue and analysis of circulating cell-free DNA (cfDNA) has a promising role for the identification of mechanisms of resistance. Methods Sixteen patients progressed during ALK-TKI were enrolled. After progression, blood was collected and DNA was extracted from plasma using QIAamp circulating nucleic acid kit (Qiagen®) and tested for ALK secondary mutations and KRAS exon 12 mutations using the Digital Droplet PCR (ddPCR – BioRad®). Results All patients were stage IV adenocarcinoma; 11 female and 5 male. Nine were never-smokers and 7 former-smokers. Median age was 53 yrs (range 40–81). Fifteen patients received crizotinib and 1 ceritinib. ALK-TKIs was administered mainly as second-line, in 2 cases as first and in the remaining as third-line therapy. Twelve patients had partial response, 3 stable disease, one progressed. Median PFS was 8 months. In 12 cases brain was a site of progression and only 5 patients had a tumor site that could potentially undergo re-biospy. ALK secondary mutations were identified in 4 patients. One showed both p.L1196M and p.G1269A mutations which levels decreased after 2 months of therapy with second generation ALK-TKI, along with tumor response. The second and the third patient had p.L1196M and p.G1269A, respectively. The 4th patient showed p.F1174L after initiation of second generation ALK-TKI. A total of 9 patients KRAS mutations p.G12D or p.G12V appeared in cfDNA at the time of resistance to TKI, 3 of them presented both ALK and KRAS mutations. Conclusions ddPCR can detect resistance mutations in cfDNA of ALK+ NSCLC and is an effective alternative to re-biopsy. The assessment of mutant allele burden could be used for response monitoring during treatment. Moreover, KRAS mutations may play a role in resistance to ALK-TKIs
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