Evaluation of PD-L1 expression in circulating tumor cells (CTC) from head and neck and gastric cancer patients treated in a single institution

• Grant number: 17/18721-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2017
• End date: February 25, 2018
• Field of knowledge: Biological Sciences - Biology
• Principal Investigator: Ludmilla Thomé Domingos Chinen
• Grantee: Camila Ribeiro de Luiz
• Host Institution: A C Camargo Cancer Center. Fundação Antonio Prudente (FAP). São Paulo , SP, Brazil

Abstract

Gastric cancer is one of the leading causes of cancer death in the world. According to INCA, in Brazil these tumors appear third in the incidence among men and in fifth among women. Malignant tumors of the head and neck have been the sixth most common cancer in the world, with 650,000 new cases per year. In its coverage, 60% of patients with squamous cell carcinoma of the head and neck are present in the locally advanced tumor. A major risk factor for tumor progression in most epithelial tumors, for example, is a spread of tumor cells in the blood. How Circulating Tumor Cells (CTCs) are responsible for the spread of cancer, and can circulate in the blood for months or even years before the development of metaphors. Its technique of isolation is a great challenge, for this reason, there are few studies on the subject. One technique for isolation of CTCs used in AC Camargo Cancer Center is ISET (Isolation by Cell Size of Epithelial Tumors) that isolates as CTCs by filtration, with the difference in size between the cells and the other components of the blood. Many studies, including our group, have evaluated a protein expression of invasion markers and resistance to treatment in CTCs (Chinen et al., 2013, Abdallah et al., 2015, Abdallah et al., 2016). Recently, Gatalica et.al. (2014) reported that tumor cells from different sites, such as sarcomas and carcinomas, acquire the ability to express PD-L1 (programmed death ligand 1), rendering them resistant to chemotherapies and the immune system. In the present study, 40 patients were sampled from 2014 to 2016, with locally advanced, non-metastatic tumors, of which 20 were head and neck submitted to definitive chemoradiotherapy and 20 were submitted to neoclinic chemotherapy. The objectives are the expression of PD-L1 in CTCs, counting CTCs and leukocytes patients, correlating them with progression-free survival (PFS).It is expected that through the design, a PD-L1 therapy to be used for this type of treatment, and as CTCs and an expression of PD-L1 in these cells as being treatment-response blood biomarkers. (AU)