Neurodevelopmental and other phenotypes recurrently associated with heterozygous BAZ2B loss-of-function variants.

The bromodomain adjacent to zinc finger 2B (BAZ2B) gene encodes a chromatin remodeling protein that has been shown to perform a variety of regulatory functions. It has been proposed that loss of BAZ2B function is associated with neurodevelopmental phenotypes, and some recurrent structural birth defects and dysmorphic features have been documented among individuals carrying heterozygous loss-of-function BAZ2B variants. However, additional evidence is needed to confirm that these phenotypes are attributable to BAZ2B deficiency. Here, we report 10 unrelated individuals with heterozygous deletions, stop-gain, frameshift, missense, splice junction, indel, and start-loss variants affecting BAZ2B. These included a paternal intragenic deletion and a maternal frameshift variant that were inherited from mildly affected or asymptomatic parents. The analysis of molecular and clinical data from this cohort, and that of individuals previously reported, suggests that BAZ2B haploinsufficiency causes an autosomal dominant neurodevelopmental syndrome that is incompletely penetrant. The phenotypes most commonly seen in association with loss of BAZ2B function include developmental delay, intellectual disability, autism spectrum disorder, speech delay-with some affected individuals being non-verbal-behavioral abnormalities, seizures, vision-related issues, congenital heart defects, poor fetal growth, and an indistinct pattern of dysmorphic features in which epicanthal folds and small ears are particularly common.

Low risk of embryonic and other cancers in PIK3CA-related overgrowth spectrum: Impact on screening recommendations.

The PIK3CA-related overgrowth spectrum (PROS) encompasses various conditions caused by mosaic activating PIK3CA variants. PIK3CA somatic variants are also involved in various cancer types. Some generalized overgrowth syndromes are associated with an increased risk of Wilms tumor (WT). In PROS, abdominal ultrasound surveillance has been advocated to detect WT. We aimed to determine the risk of embryonic and other types of tumors in patients with PROS in order to evaluate surveillance relevance. We searched the clinical charts from 267 PROS patients for the diagnosis of cancer, and reviewed the medical literature for the risk of cancer. In our cohort, six patients developed a cancer (2.2%), and Kaplan Meier analyses estimated cumulative probabilities of cancer occurrence at 45 years of age was 5.6% (95% CI = 1.35%-21.8%). The presence of the PIK3CA variant was only confirmed in two out of four tumor samples. In the literature and our cohort, six cases of Wilms tumor/nephrogenic rests (0.12%) and four cases of other cancers have been reported out of 483 proven PIK3CA patients, in particular the p.(His1047Leu/Arg) variant. The risk of WT in PROS being lower than 5%, this is insufficient evidence to recommend routine abdominal imaging. Long-term follow-up studies are needed to evaluate the risk of other cancer types, as well as the relationship with the extent of tissue mosaicism and the presence or not of the variant in the tumor samples.

Taxane rechallenge during metastatic disease in HER-2 negative breast cancer patients: Clinical activity, tolerance and survival results.

BACKGROUND: Taxanes are major drugs for metastatic breast cancer (MBC) treatment, and are generally well tolerated, making them attractive for therapeutic reintroduction (rechallenge) during metastatic course. In view of the paucity of current literature, we questioned the usefulness of taxane rechallenge in a population of patients previously treated with taxanes in a metastatic setting. METHODS: From the local database of a French cancer center, we retrospectively identified 756 patients diagnosed with ER+/HER2-, or triple negative MBC, and treated between 2008 and 2021. Among them, 58 patients (7.8%) were rechallenged with taxanes. Clinical characteristics, response rates, and survival were retrospectively evaluated and compared to patients who received taxanes only once. RESULTS: Compared to non-rechallenged population, patients treated with taxane rechallenge were significantly younger, with better general status, and received more treatment. First taxane exposure led to better tumor response and was more frequently discontinued for reasons other than progression, compared to the non-rechallenged population. Taxane rechallenge led to an objective response rate of 27.6%, and a clinical benefit rate of 46.6%, with a median progression-free survival (PFS) of 5.7 months, and a median overall survival (OS) of 11.6 months. We also found a PFS2/PFS1 ratio >1.3 in 55.2% of the rechallenge population. CONCLUSION: Although only a minority of MBC patients are concerned, taxane rechallenge appears to be a pragmatic option with an acceptable tolerance, and good efficacy, especially when these drugs have shown clinical activity earlier in the disease course, and/or have been stopped for reasons other than progression.

Clinical Utility of Genomic Tests Evaluating Homologous Recombination Repair Deficiency (HRD) for Treatment Decisions in Early and Metastatic Breast Cancer.

Breast cancer is the most frequently occurring cancer worldwide. With its increasing incidence, it is a major public health problem, with many therapeutic challenges such as precision medicine for personalized treatment. Thanks to next-generation sequencing (NGS), progress in biomedical technologies, and the use of bioinformatics, it is now possible to identify specific molecular alterations in tumor cells-such as homologous recombination deficiencies (HRD)-enabling us to consider using DNA-damaging agents such as platinum salts or PARP inhibitors. Different approaches currently exist to analyze impairment of the homologous recombination pathway, e.g., the search for specific mutations in homologous recombination repair (HRR) genes, such as BRCA1/2; the use of genomic scars or mutational signatures; or the development of functional tests. Nevertheless, the role and value of these different tests in breast cancer treatment decisions remains to be clarified. In this review, we summarize current knowledge on the clinical utility of genomic tests, evaluating HRR deficiency for treatment decisions in early and metastatic breast cancer.

Advancing precision oncology through systematic germline and tumor genetic analysis: The oncogenetic point of view on findings from a prospective multicenter clinical trial of 666 patients.

INTRODUCTION: With the emergence of targeted therapies, there is a need to accurately identify more tumor biomarkers. The EXOMA trial was designed to offer tumor and germline exome sequencing (ES) to patients with solid malignant tumors and facing therapeutic failure. As hereditary cancer predispositions could be identified, with genetic counseling and health management implications, a genetic consultation was systematically established. This design needs to be discussed as genetic human resources are limited and indication of theranostic tests will increase. METHODS: Genetic counseling was conducted within 15 days following inclusion in the study for patients recruited between December 2015 and July 2019. In silico analyses from theranostic ES were limited to 317 genes involved in oncogenesis, from both tumor and blood DNA. RESULTS: Six hundred and sixty six patients had a genetic consultation before ES. In 65/666 patients, 66 germline pathogenic or likely pathogenic (P/LP) variants were identified in 16 actionable genes and seven non-actionable genes according to French guidelines. 24/65 patients had previously received genetic analysis for diagnostic purposes, and for 17 of them, a P/LP variant had already been identified. Among the 48/65 remaining cases for which the EXOMA protocol revealed a previously unknown P/LP variant, only 19 met the criteria for genetic testing for inherited cancer risk after familial survey. These criteria had not been identified by the oncologist in 10 cases. In 21/65 cases, the variant was considered incidental. DISCUSSION: In 7.4% of patients, an undiagnosed hereditary genetic predisposition was identified, whether or not related to the clinical presentation, and germline analysis impacted oncological management for only 6.3% of the cohort. This low percentage should be weighed against the burden of systematic genetic consultation and urgent circuits. Information or training tools to form oncologists to the prescription of germline genetic analyses should be explored, as well as information supports and patient preferences.

Optimization of G-CSF dosing schedule in patients treated with eribulin: a modeling approach.

BACKGROUND: Granulocyte colony-stimulating factors (G-CSF) are commonly given to limit chemotherapy-induced neutropenia, but, in case of weekly chemotherapy such as eribulin, their administration schedules remain empirical. OBJECTIVES: This pharmacokinetic/pharmacodynamic (PK/PD) study was conducted to establish the effect of different G-CSF regimens on neutropenia's incidence for patients treated by eribulin, to propose an optimal G-CSF dosing schedule. METHODS: A population PK/PD model was developed to describe absolute neutrophil counts' (ANC) time course in 87 cancer patients receiving eribulin. The structural model considered ANC dynamics, neutropenic effect of eribulin and stimulating effect of G-CSF. Final model estimates were used to calculate neutropenia's incidence following different G-CSF dosing schedules for 1000 virtual subjects. RESULTS: The final model successfully described most of the ANC time course for all patients. Simulations showed that a single G-CSF administration 48 h after each eribulin injection reduced the risk of severe neutropenia from 29.7 to 5.2%. Five days of G-CSF only after the second eribulin injection or no G-CSF administration induces similar incidence of neutropenia. CONCLUSION: Simulations showed a single G-CSF administration 48 h after the end of each eribulin injection seems to be the optimal schedule to reduce eribulin-induced neutropenia. However, the new administration scheme should be tested in real life to evaluate its pertinence. TRIAL REGISTRATION: Eudract 2015-001753-32, 2015/01/26.

Detection of relevant pharmacogenetic information through exome sequencing in oncology.

Background: Germline sequencing of individual genomes can detect alleles responsible for adverse drug reactions (ADRs) in relation to chemotherapy, targeted agents, antiemetics or pain treatment. Materials & methods: To evaluate the interest of such pharmacogenetic information, the authors retrospectively analyzed genes known to have an impact on cancer therapy in a cohort of 445 solid cancers patients. Results: Six patients treated with 5-fluorouracil carrying one DPYD variant classified as 1A showed decreased drug mean clearance (p = 0.01). Regarding CYP2D6, all patients (n = 5) with predicted CYP2D6 poor or ultra-rapid metabolizer status experienced adverse drug reactions related to opioid therapy. Conclusion: Genomic germline sequencing performed for theragnostic issues in patients with a solid tumor, can provide relevant information about common pharmacogenetic alleles.

Implementation and use of whole exome sequencing for metastatic solid cancer.

BACKGROUND: Genomically-guided clinical trials are performed across different tumor types sharing genetic mutations, but trial organization remains complex. Here we address the feasibility and utility of routine somatic and constitutional exome analysis in metastatic cancer patients. METHODS: Exoma trial (NCT02840604) is a multicenter, prospective clinical trial. Eligible patients presented a metastatic cancer progressing after at least one line of systemic therapy. Constitutional genetics testing required geneticist consultation. Somatic and germline exome analysis was restricted to 317 genes. Variants were classified and molecular tumor board made therapeutic recommendations based on ESMO guidelines. Primary endpoint was the feasibility of the approach evaluated by the proportion of patient that received a therapeutic proposal. FINDINGS: Between May 2016 and October 2018, 506 patients were included. Median time required for tumor sample reception was 8 days. Median time from sample reception to results was 52 days. Somatic analysis was performed for 456 patients (90.1%). Both somatic and constitutional analyses were successfully performed for 386 patients (76.3%). In total, 342 patients (75%) received a therapeutic proposal. Genetic susceptibility to cancer was found in 35 (9%) patients. Only, 79 patients (23.1%) were treated with NGS matched therapy mainly PI3K/AKT/mTOR inhibitors 22 (27.8%), followed by PARP inhibitors 19 (24.1%), antiangiogenics 17 (21.5%), MEK inhibitors 7 (8.9%) and immunotherapy 5 (6.3%). Matched treatment was finally stopped because of disease progression 50 (63%), treatment toxicity 18 (23%), patients' death 4 (5%). PFS2/PFS1 ratio was > 1,3 for 23,5% of patients treated with the NGS matched therapy and 23,7% of patients treated with standard therapy. INTERPRETATION: Study shows that exome analysis is feasible in cancer routine care. This strategy improves detection of genetic predispositions and enhances access to target therapies. However, no differences were observed between PFS ratios of patients treated with matched therapy versus standard therapy. FUNDING: This work was funding by the centre Georges Francois Leclerc.

Anti-MEK and Anti-EGFR mAbs in RAS-Mutant Metastatic Colorectal Cancer: Case Series and Rationale.

KRAS (Kirsten rat sarcoma viral oncogene) or BRAF (v-raf murine sarcoma viral oncogene homolog B1) constitutive activation leads to anti-EGFR (epidermal growth factor receptor) therapy resistance of metastatic colorectal cancer patients. In this article we investigate the effects of anti-MEK (mitogen-activated protein kinase) antibody (trametinib) combined with anti-EGFR (cetuximab) on colon cancer cell lines with different RAS statuses. Even though cetuximab has no effect on RAS cell viability and ERK (extracellular-signal-regulated kinase) phosphorylation (one of the last kinases of the EGFR pathway), trametinib can induce cell death and inhibit the activation of ERK alone or in combination with cetuximab. In a more pathologic context, we observed that KRAS colon cancer patient biopsies treated ex vivo with trametinib and cetuximab also present less ERK phosphorylation. Finally, nine ovarian, endometrial and colon cancer patients with different KRAS statuses were treated with anti-EGFR/anti-MEK combination off label after molecular tumor board decision. KRAS exon 2 patients have significantly longer PFS (progression-free survival) than with previous lines of treatments. We believe that such observations provide a rationale for designing a clinical trial to test this association in RAS exon 2 mutated cancers.