Previous studies in patients with mature B-cell lymphomas (MBCL) have shown that pathogenic TP53 aberrations are associated with inferior chemotherapeutic efficacy and survival outcomes. In solid... Show morePrevious studies in patients with mature B-cell lymphomas (MBCL) have shown that pathogenic TP53 aberrations are associated with inferior chemotherapeutic efficacy and survival outcomes. In solid malignancies, p53 immunohistochemistry is commonly used as a surrogate marker to assess TP53 mutations, but this correlation is not yet well-established in lymphomas. This study evaluated the accuracy of p53 immunohistochemistry as a surrogate marker for TP53 mutational analysis in a large real-world patient cohort of 354 MBCL patients within routine diagnostic practice. For each case, p53 IHC was assigned to one of three categories: wild type (staining 1-50% of tumor cells with variable nuclear staining), abnormal complete absence or abnormal overexpression (strong and diffuse staining > 50% of tumor cells). Pathogenic variants of TP53 were identified with a targeted next generation sequencing (tNGS) panel. Wild type p53 expression was observed in 267 cases (75.4%), complete absence in twenty cases (5.7%) and the overexpression pattern in 67 cases (18.9%). tNGS identified a pathogenic TP53 mutation in 102 patients (29%). The overall accuracy of p53 IHC was 84.5% (95% CI 80.3-88.1), with a robust specificity of 92.1% (95% CI 88.0- 95.1), but a low sensitivity of 65.7% (95% CI 55.7-74.8). These results suggest that the performance of p53 IHC is insufficient as a surrogate marker for TP53 mutations in our real-world routine diagnostic workup of MBCL patients. By using p53 immunohistochemistry alone, there is a significant risk a TP53 mutation will be missed, resulting in misevaluation of a high-risk patient. Therefore, molecular analysis is recommended in all MBCL patients, especially for further development of risk-directed therapies based on TP53 mutation status. Show less
Hagenaars, S.C.; Groot, S. de; Cohen, D.; Dekker, T.J.A.; Charehbili, A.; Kranenbarg, E.M.K.; ... ; Dutch Breast Can 2021
The tumor-stroma ratio (TSR) has proven to be a strong prognostic factor in breast cancer, demonstrating better survival for patients with stroma-low tumors. Since the role of the TSR as a... Show moreThe tumor-stroma ratio (TSR) has proven to be a strong prognostic factor in breast cancer, demonstrating better survival for patients with stroma-low tumors. Since the role of the TSR as a predictive marker for neoadjuvant chemotherapy outcome is yet unknown, this association was evaluated for HER2-negative breast cancer in the prospective DIRECT and NEOZOTAC trials. The TSR was assessed on 375 hematoxylin and eosin-stained sections of pre-treatment biopsies. Associations between the TSR and chemotherapy response according to the Miller-Payne (MP) grading system, and between the TSR and pathological response were examined using Pearson's chi-square, Cochran-Armitage test for trend and regression analyses. A stroma-low tumor prior to neoadjuvant chemotherapy was significantly associated with a higher MP score (P = .005). This relationship remained significant in the estrogen receptor (ER)-negative subgroup (P = .047). The univariable odds ratio (OR) of a stroma-low tumor on pathological complete response (pCR) was 2.46 (95% CI 1.34-4.51, P = .004), which attenuated to 1.90 (95% CI 0.85-4.25, P = .119) after adjustment for relevant prognostic factors. Subgroup analyses revealed an OR of 5.91 in univariable analyses for ER-negativity (95% CI 1.19-29.48, P = .030) and 1.48 for ER-positivity (95% CI 0.73-3.01, P = .281). In conclusion, a low amount of stroma on pre-treatment biopsies is associated with a higher MP score and pCR rate. Therefore, the TSR is a promising biomarker in predicting neoadjuvant treatment outcome. Incorporating this parameter in routine pathological diagnostics could be worthwhile to prevent overtreatment and undertreatment. Show less
This thesis deals with multiple aspects of breast cancer risk stratification after locoregional treatment. The first part of the thesis deals with the reproducibility of established... Show moreThis thesis deals with multiple aspects of breast cancer risk stratification after locoregional treatment. The first part of the thesis deals with the reproducibility of established pathological parameters that currently stratify breast cancer patients to low- or high risk, on the basis of which systemic therapies are considered. The reproducibility of estrogen receptor, progesterone receptor and HER2 is investigated. Additionally, prognostic implication of lymph vascular space invasion is assessed as well as its interobserver reproduciblity. Lastly, the reproducibility of Ki67 assays are determined. The second part of the thesis concerns investigations into the prognostic aspects of the tumor-associated stromal tissues. These tissues might be used to further improve breast cancer risk stratifications as well as help determine tumor susceptibility to systemic treatments. The prognostic implications of the tumor-stroma ratio is investigated. Proteomic studies into the tumor-associated stroma is described as well as a work-flow for investigating metabolic interactions between the tumor epithelium and tumor stroma. The prognostic significance of TGF-beta signaling is also investigated. Show less
Dekker, T.J.A.; Borg, S. ter; Hooijer, G.K.J.; Meijer, S.L.; Wesseling, J.; Boers, J.E.; ... ; Vijver, M.J. van de 2015
