ErbB2 and p53 expression as predictive factors in high-grade osteosarcoma

Background: Overexpression and gene amplification of HER-2 have been shown to be associated with poor prognosis in many cancers. Studies have revealed that HER-2 overexpression is associated with poor prognosis in osteosarcoma. The object of the current study is to assess the correlation of HER-2 or p53 overexpression with the histological response to preoperative chemotherapy and event-free survival Methods: We performed immunohistochemical staining (HER-2 and p53) on paraffin-embedded tissue obtained from 17 patients whom were treated preoperatively with 3 cycles of cisplatin 75-100 mg/m2 (day 1) + doxorubicin 25 mg/m2 (days 1-3). Membranous and cytoplasmic staining for HER-2 was separately done and a more than 25% staining was considered positive. P53 was categorized as positive, weakly positive and negative. The patients were categorized according to chemotherapy response (Huvos grading) good response (grade 3-4) and poor response (grade 1-2). Results: No positive membranous HER-2 staining was detected. No relationship between cytoplasmic staining and chemotherapy response was found (p=0.662). Expression ofp53 did not correlate with histological response or patient s eventfree survival. Cox-proportional hazards regression analysis was performed to estimate possible risk factors (sex, age, HER-2, p53, Response) for event-free survival Only histological response was a significant risk factor (p=0.024). Conclusion: Overexpression of HER-2 and p53 in high-grade osteosarcoma was not predictive of response to preoperative chemotherapy. In relation to event-free survival, only good response to chemotherapy was found to be a statistically significant prognostic factor