Overexpression of PIK3CA impacts global survival of patients with HER2 subtype breast carcinoma

• Autor(a) principal: Felicidade, Sidnei Iensen
• Data de Publicação: 2020
• Outros Autores: Pilar, Emily Ferreira Salles, Teixeira, Joara Predebom Flores, Watte, Guilherme, Remonatto, Gabriela, Alves, Rita de Cássia Sant’Anna, Roehe, Adriana Vial
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/220832
• topic: Neoplasias da mama; Imuno-histoquímica; Sobrevida; Biomarcadores; Breast cancer; Immunohistochemistry; HER2; PIK3CA; PTEN; Survival

Purpose: To investigate the expression of proteins fosfatidilinositol-4,5-bifosfate 3-quinase (PIK3CA) and phosphatase and tensin homolog (PTEN) in HER2-positive breast cancer and verify their associations with clinical and pathological variables. Methods: We assessed PTEN and PIK3CA status using immunohistochemistry (IHC), which was performed in formalin-fixed paraffin-embedded biopsies from 50 patients with HER2-positive breast cancer. Medical records were studied for collection of clinical-pathological information, including overall survival (OS). The HIC markers PTEN and PIK3CA were analyzed semi-quantitatively by two blinded independent researchers. The relationship between the variables were evaluated using the chi-square test and Kaplan-Meier curves plus log-rank test for survival. Results: In IHC, the expression level of PIK3CA was 86%, and loss of PTEN expression was observed in 46% of the cases. The expression of the markers showed no significant correlation with each other or with the clinical and pathological parameters studied: tumor grade, staging, ER, PR, Ki67 and recurrence. The highest expression of PIK3CA was associated with lower number of deaths (p=0.016) and longer OS of patients (p=0.001). The PTEN marker showed no significant effect on OS. Conclusions: The PIK3CA expression showed a protective effect in relation to the OS of patients with HER2-positive breast cancer.