ESTRO 2024 - Abstract Book

S5386

Radiobiology - Tumour biology

ESTRO 2024

Conclusion:

We report a novel yet-undescribed role for SPOP gene in maintaining genomic stability through regulation of chromatin accessibility to ensure an efficient and timely transcription. The findings of the current study open new avenues for possible treatment options for patients with SPOP-deficient prostate cancer.

Keywords: prostate cancer, genomic instability, chromatin

1806

Proffered Paper

Transcriptome and tumor immune infiltrate in breast cancer treated with preoperative radiosurgery

Monica Mangoni 1 , Assia Duatti 1 , Saverio Caini 2 , Giovanni Fiorito 3 , Giulia Salvatore 1 , Giulia Anichini 1 , Mariangela Sottili 1 , Luca Visani 4 , Giulio Francolini 4 , Vanessa Di Cataldo 4 , Mauro Loi 4 , Carlotta Becherini 4 , Viola Salvestrini 4 , Simonetta Bianchi 5 , Laura Masi 6 , Raffaella Doro 6 , Jacopo Nori 7 , Lorenzo Orzalesi 8 , Marco Bernini 8 , Daniela Greto 4 , Gabriele Simontacchi 4 , Isacco Desideri 1 , Icro Meattini 1 , Lorenzo Livi 1 1 University of Florence, Experimental and Clinical Biomedical Sciences “M. Serio”, Florence, Italy. 2 Institute for Cancer Research, Prevention, and Clinical Network, ISPRO, Florence, Italy. 3 IRCCS Istituto Giannina Gaslini, Clinical Bioinformatics Unit, Genoa, Italy. 4 Azienda Ospedaliero Universitaria Careggi, Radiation Oncology Unit, Florence, Italy. 5 University of Florence, Division of Pathological Anatomy, Department of Health Sciences, Florence, Italy. 6 Istituto Fiorentino di Cura e Assistenza (IFCA), CyberKnife Center, Florence, Italy. 7 Azienda Ospedaliero Universitaria Careggi, Diagnostic Senology Unit, Florence, Italy. 8 Azienda Ospedaliero Universitaria Careggi, Breast Surgery Unit, Florence, Italy

Purpose/Objective:

ROCK is a phase II trial (NCT03520894) on the feasibility, safety, and activity of a single 21 Gy preoperative robotic radiosurgery (prRS) in early breast cancer (BC) patients, 50+ years old, hormonal receptors positive/human epidermal growth factor receptor 2 negative (HR+/HER2-), sized up to 25 mm. A translational study was carried out on enrolled patients with the aim to explore the transcriptome on tumor samples before irradiation and the tumor-immune microenvironment (TIME) on tumor samples before and after irradiation.

Material/Methods:

A total of 70 patients were recruited and 22 patients were successfully treated with prRS. Fresh pre-treatment tumor biopsies and fresh post-radiosurgery and post-operative tumor samples were retrieved. For immunohistochemistry (IHC) analysis, pre-radiosurgery biopsies and post-operative tumors were dissected, 4% PFA-fixed and paraffin embedded. Sections were stained with specific antibodies allowing the evaluation of the expression of different