Origin of Residual Tumor Masses in BRCA1/2-Driven Ovarian Carcinomas Treated by Neoadjuvant Chemotherapy: Selection of Preexisting BRCA1/2-Proficient Tumor Cells but Not the Gain of Second ORF-Restoring Mutation

Abstract

Introduction: Tubo-ovarian carcinomas (OCs) are highly sensitive to platinum-based neoadjuvant chemotherapy (NACT) but almost never demonstrate complete pathologic response. Methods: We analyzed paired primary and residual tumor tissues from 30 patients with hereditary BRCA1/2-driven OCs (BRCA1: 17; BRCA2: 13), who were treated by carboplatin/paclitaxel NACT (median number of cycles: 3, range 3-6). BRCA1/2 and TP53 genes were analyzed by the next-generation sequencing (NGS). The ratio between TP53 mutation-specific vs. wild-type reads was considered to monitor the proportion of tumor and non-tumor cells in the tissue sample, and the ratio between BRCA1/2 mutated and wild-type reads was used to estimate the presence of cells with the loss or retention of heterozygosity (LOH or ROH, respectively). Results: All 30 OCs had BRCA1/2 LOH in primary tumor and carried somatic TP53 mutation. Twenty-eight OCs had sufficient tumor cell cellularity in the post-NACT tissue to evaluate the ratio between mutated and wild-type BRCA1/2 alleles. Five (18%) out of 28 informative tumor pairs showed transition from LOH to ROH during NACT presumably affecting all or the vast majority of residual tumor cells. There were no signals of the emergence of a second open reading frame (ORF) restoring BRCA1/2 mutation. Conclusion: Chemonaive BRCA1/2-driven carcinomas may contain a fraction of tumor cells with preserved BRCA1/2 heterozygosity. NACT can cause a selection of pre-existing BRCA1/2-proficient tumor cells, without gaining secondary reversal BRCA1/2 mutations.

Ultrasound-guided robotic surgical procedures: a systematic review

“…In this context, IOUS has emerged as the imaging modality of choice facilitated by the introduction of articulated robotic instruments to handle ultrasound probes [ 11 ]. The augmentation and fusion of imaging modalities are especially beneficial for delineating healthy and neoplastic tissue in oncological surgery [ 12 ]. The navigation of drop-in ultrasound probes manoeuvred by articulated robotic graspers provides access to anatomical spaces and angles that are inconvenient for relatively rigid laparoscopic probes.…”