Immunohistochemical Analysis of Prostate Apoptosis Response-4 (Par-4) in Mexican Women with Breast Cancer: A Preliminary Study

Background and Aims We undertook this study to compare the expression level of prostate apoptosis response-4 (Par-4) among patient outcome in two groups of women with breast cancer (short and long survival) and two groups without breast cancer (benign lesion and control). Methods We included breast specimens with nonhistological abnormalities (eight samples) as a control group. Semiquantitative and quantitative analysis of immunohistochemical staining by image analysis software were used to study the intensity of Par-4 expression. Both methods produced similar results ( p >0.05). Results No significant expression of Par-4 was observed in normal breast tissue. Benign lesions and breast cancer tissue showed strong nuclear expression of Par-4, predominantly on epithelial cells and specifically in ductal cells. Par-4 expression was lower in myoepithelial cells and there was no appreciable stromal staining. Significantly less Par-4 reactivity was detected in tissue from patients with a short survival compared with patients with benign lesions and those with a long survival. Conclusions Our findings suggest that a lower expression level of Par-4 is related to an unfavorable prognosis. A larger prospective study of samples of all patient groups with a longer follow-up is needed to validate this finding.