Publications by authors named "Jolien S de Groot"

Objective: The collection of comprehensive data from post-authorisation trials for conditionally authorised anticancer medicines is frequently delayed. This raises questions about the feasibility of post-authorisation randomised controlled trials (RCTs) that aim to address remaining uncertainties. Therefore, this study explored factors that facilitate or impede the feasibility of post-authorisation RCTs from the perspective of stakeholders directly involved in the design, medical-ethical approval, and conduct of these RCTs.

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Purpose: Retrospective studies suggest that immunosuppressive treatment of immune-related adverse events (irAEs) impairs survival in patients with melanoma who received immune checkpoint inhibitors. Here, we study this association across tumor types using data from six international phase II/III registrational trials.

Methods: A post hoc analysis was performed on individual patient data from the anti-programmed cell death-1 (anti-PD-1) + anti-cytotoxic T lymphocyte-associated protein-4 (anti-CTLA-4) treatment arms of six clinical trials (CheckMate-067, -142, -214, -648, -743, and -9LA).

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Although mutational inactivation of E-cadherin (CDH1) is the main driver of invasive lobular breast cancer (ILC), approximately 10-15% of all ILCs retain membrane-localized E-cadherin despite the presence of an apparent non-cohesive and invasive lobular growth pattern. Given that ILC is dependent on constitutive actomyosin contraction for tumor development and progression, we used a combination of cell systems and in vivo experiments to investigate the consequences of α-catenin (CTNNA1) loss in the regulation of anchorage independence of non-invasive breast carcinoma. We found that inactivating somatic CTNNA1 mutations in human breast cancer correlated with lobular and mixed ducto-lobular phenotypes.

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deficiency predisposes to the development of invasive breast cancer. In mutation carriers this risk can increase up to 80%. Currently, bilateral prophylactic mastectomy and prophylactic bilateral salpingo-oophorectomy are the only preventive, albeit radical invasive strategies to prevent breast cancer in BRCA mutation carriers.

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Spatiotemporal activation of RhoA and actomyosin contraction underpins cellular adhesion and division. Loss of cell-cell adhesion and chromosomal instability are cardinal events that drive tumour progression. Here, we show that p120-catenin (p120) not only controls cell-cell adhesion, but also acts as a critical regulator of cytokinesis.

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Introduction: Nipple fluid aspiration provides direct non-invasive sampling of fluid from the mammary ductal system, where the majority of breast cancers originate. DNA promoter hypermethylation ("methylation") occurs early and at high frequency in breast carcinogenesis, bearing the potential as a biomarker for cancer detection at its earliest stages. We assessed methylation in nipple fluid from breasts of healthy women, of women with sporadic breast cancer and of their contralateral breasts.

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Purpose: DNA promoter hypermethylation of tumor suppressor genes is known to occur early in cancer development, including breast cancer. To improve early breast cancer detection, we aimed to investigate whether the identification of DNA promoter hypermethylation might be of added value.

Methods: The methylation status of a panel of 19 candidate genes (AKR1B1, ALX1, ARHGEF7, FZD10, GHSR, GPX7, GREM1, GSTP1, HOXD1, KL, LHX2, MAL, MGMT, NDRG2, RASGRF2, SFRP1, SFRP2, TM6SF1 and TMEFF2) was determined in formalin-fixed paraffin-embedded normal breast and breast cancer tissue samples using gel-based methylation-specific PCR (MSP).

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Intratumor heterogeneity may lead to sampling bias and may present major challenges to personalized medicine and biomarker development. Despite many studies investigating genetic heterogeneity, epigenetic intratumor heterogeneity of promoter hypermethylation has only rarely been examined in breast cancer. To examine clonal intratumor heterogeneity of promotor hypermethylation, we performed methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) for 24 established tumor-suppressor genes on multiple spatially separated samples obtained from 21 primary breast carcinomas.

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