Early-Stage Breast Cancer Detection in Breast Milk.

Breast cancer occurring during pregnancy (PrBC) and postpartum (PPBC) is usually diagnosed at more advanced stages compared with other breast cancer, worsening its prognosis. PPBC is particularly aggressive, with increased metastatic risk and mortality. Thus, effective screening methods to detect early PrBC and PPBC are needed. We report for the first time that cell-free tumor DNA (ctDNA) is present in breast milk (BM) collected from patients with breast cancer. Analysis of ctDNA from BM detects tumor variants in 87% of the cases by droplet digital PCR, while variants remain undetected in 92% of matched plasma samples. Retrospective next-generation sequencing analysis in BM ctDNA recapitulates tumor variants, with an overall clinical sensitivity of 71.4% and specificity of 100%. In two cases, ctDNA was detectable in BM collected 18 and 6 months prior to standard diagnosis. Our results open up the potential use of BM as a new source for liquid biopsy for PPBC detection. SIGNIFICANCE: For the first time, we show that BM obtained from patients with breast cancer carries ctDNA, surpassing plasma-based liquid biopsy for detection and molecular profiling of early-stage breast cancer, even prior to diagnosis by image. See related commentary by Cunningham and Turner, p. 2125. This article is featured in Selected Articles from This Issue, p. 2109.

Human Metastatic Cholangiocarcinoma Patient-Derived Xenografts and Tumoroids for Preclinical Drug Evaluation.

PURPOSE: Cholangiocarcinoma (CCA) is usually diagnosed at advanced stages, with limited therapeutic options. Preclinical models focused on unresectable metastatic CCA are necessary to develop rational treatments. Pathogenic mutations in IDH1/2, ARID1A/B, BAP1, and BRCA1/2 have been identified in 30%-50% of patients with CCA. Several types of tumor cells harboring these mutations exhibit homologous recombination deficiency (HRD) phenotype with enhanced sensitivity to PARP inhibitors (PARPi). However, PARPi treatment has not yet been tested for effectiveness in patient-derived models of advanced CCA. EXPERIMENTAL DESIGN: We have established a collection of patient-derived xenografts from patients with unresectable metastatic CCA (CCA_PDX). The CCA_PDXs were characterized at both histopathologic and genomic levels. We optimized a protocol to generate CCA tumoroids from CCA_PDXs. We tested the effects of PARPis in both CCA tumoroids and CCA_PDXs. Finally, we used the RAD51 assay to evaluate the HRD status of CCA tissues. RESULTS: This collection of CCA_PDXs recapitulates the histopathologic and molecular features of their original tumors. PARPi treatments inhibited the growth of CCA tumoroids and CCA_PDXs with pathogenic mutations of BRCA2, but not those with mutations of IDH1, ARID1A, or BAP1. In line with these findings, only CCA_PDX and CCA patient biopsy samples with mutations of BRCA2 showed RAD51 scores compatible with HRD. CONCLUSIONS: Our results suggest that patients with advanced CCA with pathogenic mutations of BRCA2, but not those with mutations of IDH1, ARID1A, or BAP1, are likely to benefit from PARPi therapy. This collection of CCA_PDXs provides new opportunities for evaluating drug response and prioritizing clinical trials.

ESMO Scale for Clinical Actionability of Molecular Targets Driving Targeted Treatment in Patients with Cholangiocarcinoma.

PURPOSE: Treatment options for advanced cholangiocarcinoma are limited and prognosis is poor. Cholangiocarcinomas are highly heterogeneous at the molecular level, with divergent patterns between intrahepatic and extrahepatic forms, intrahepatic being particularly rich in actionable alterations. We compared survival in patients with advanced cholangiocarcinoma harboring alterations matched to targeted drugs, with patients harboring nonactionable alterations. EXPERIMENTAL DESIGN: Patients with cholangiocarcinoma treated between 2011 and 2020 at one institution, with available molecular analyses, were retrospectively reviewed. Genomic alteration actionability was classified according to the ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT) and correlated with efficacy endpoints. RESULTS: Of 327 patients included, 78.9% had intrahepatic cholangiocarcinoma, 97.9% had received chemotherapy for metastatic disease. Actionable molecular alterations per ESCAT were identified in 184 patients (56.3%), including IDH1 mutations and FGFR2 fusions (23.1% and 8.0% of patients with intrahepatic cholangiocarcinoma, respectively). Median overall survival in 50 patients with ESCAT I-IV alterations who received matched therapy (48 with intrahepatic cholangiocarcinoma) was 22.6 months [95% confidence interval (CI), 20.1-32.8], compared with 14.3 months (95% CI 11.9-18.1) in 130 patients without actionable ESCAT alterations (HR, 0.58; 95% CI, 0.40-0.85; P = 0.005). Among patients receiving matched targeted therapy, median progression-free survival was longer for patients with alterations classified as ESCAT I-II compared with ESCAT III-IV (5.0 vs. 1.9 months; HR, 0.36; 95% CI, 0.15-0.87; P = 0.02). CONCLUSIONS: ESCAT represents a tool to guide clinicians in fine-tuning use of molecular profiling data to choose matched targeted therapies. Our data demonstrate that targeted treatment administered per alteration actionability according to ESCAT is associated with improved survival in cholangiocarcinoma, particularly in ESCAT I-II intrahepatic cholangiocarcinoma.

Activity of HSP90 Inhibiton in a Metastatic Lung Cancer Patient With a Germline BRCA1 Mutation.

Heat shock proteins (HSPs) are molecular chaperones that maintain proteins in their correct conformation to ensure stability and protect carcinoma cells from apoptosis. HSP90 inhibitors (HSP90i) block multiple targets simultaneously, and despite responses in a selected population, no HSP90i have yet been approved. We present a patient with a lung tumor with an exceptional response to cisplatin/gemcitabine in combination with HSP90i, which nowadays continues with HSP90i maintenance after three years. Whole-exome sequencing of the lung tumor unveiled a BRCA1/2 deficiency mutational signature, and mutation analysis confirmed a germline BRCA1 mutation. The striking efficacy of HSP90i plus chemotherapy vs chemotherapy alone was reproduced in a patient-derived xenograft (PDX) model from a breast cancer patient with a BRCA1 mutation (mean tumor volume [SD], No. of tumors: vehicle 8.38 [7.07] mm3, n = 3; HSP90i 4.18 [1.93] mm3, n = 5; cisplatin plus gemcitabine 3.31 [1.95] mm3, n = 5; cisplatin plus gemcitabine plus HSP90i 0.065 [0.076] mm3, n = 6). This case and the PDX demonstrate the efficacy for therapeutic inhibition of HSP90 in a BRCA-mutated patient, opening a new potential avenue for better identifying patients who might benefit most from HSP90i.

An in vitro tool to assess cytochrome P450 drug biotransformation-dependent cytotoxicity in engineered HepG2 cells generated by using adenoviral vectors.

Many adverse drug reactions leading to hepatotoxicity are caused by the cytochrome P450-dependent activation of non-toxic drugs or chemicals into reactive metabolites. To this end, adenoviruses were used as a tool to efficiently deliver specific CYP genes into cultured cells (i.e., human hepatoma cell line HepG2). Recombinant-defective adenoviral vectors encoding for genes CYP3A4 (Adv-CYP3A4), CYP2E1 (Adv-CYP2E1), CYP2A6 (Adv-CYP2A6) and CYP1A2 (Adv-CYP1A2) were used to confer specific CYP drug metabolic capabilities to HepG2 cells. Upgraded cells transiently expressed single specific cytochrome P450 enzymatic activities in terms of the number of the infecting virus particles used in their transduction. HepG2 cells transduced with adenoviruses and wild HepG2 cells cultured in 96 well-plates were incubated in the presence of model compounds, some of which can be metabolized to reactive metabolites. After compound exposure, cell viability was assessed by the commonly used MTT assay. The results confirm that the cell-based assay is a valuable tool in toxicology assessments and high-throughput screenings to detect cytotoxicity mediated by cytochrome P450 biotransformation in preclinical drug development. The assay also has a potential applicability in other industrial sectors such as the chemical industry.

Evaluation of uptake and transport of cationic and anionic ultrasmall iron oxide nanoparticles by human colon cells.

Nanoparticles (NPs) are in clinical use or under development for therapeutic imaging and drug delivery. However, relatively little information exists concerning the uptake and transport of NPs across human colon cell layers, or their potential to invade three-dimensional models of human colon cells that better mimic the tissue structures of normal and tumoral colon. In order to gain such information, the interactions of biocompatible ultrasmall superparamagnetic iron oxide nanoparticles (USPIO NPs) (iron oxide core 9-10 nm) coated with either cationic polyvinylamine (aminoPVA) or anionic oleic acid with human HT-29 and Caco-2 colon cells was determined. The uptake of the cationic USPIO NPs was much higher than the uptake of the anionic USPIO NPs. The intracellular localization of aminoPVA USPIO NPs was confirmed in HT-29 cells by transmission electron microscopy that detected the iron oxide core. AminoPVA USPIO NPs invaded three-dimensional spheroids of both HT-29 and Caco-2 cells, whereas oleic acid-coated USPIO NPs could only invade Caco-2 spheroids. Neither cationic aminoPVA USPIO NPs nor anionic oleic acid-coated USPIO NPs were transported at detectable levels across the tight CacoReady™ intestinal barrier model or the more permeable mucus-secreting CacoGoblet™ model.