Platinum-based chemotherapy (PBC) is the most effective cytotoxic treatment for advanced adrenocortical carcinoma (ACC). Excision repair cross complementing group 1 (ERCC1) plays a critical role in the repair of platinum-induced DNA damage. Two studies investigating the role of ERCC1 immunostaining as a predictive marker for the response to PBC in ACC had reported conflicting results. Both studies used the ERCC1-antibody clone 8F1 that later turned out to be not specific. The aim of this study was to evaluate the predictive role of ERCC1 with a new specific antibody in a larger series of ACC.
Design and methods
146 ACC patients with available FFPE slides were investigated. All patients underwent PBC (median cycles = 6), including cisplatin (n = 131) or carboplatin (n = 15), in most cases combined with etoposide (n = 144), doxorubicin (n = 131) and mitotane (n = 131). Immunostaining was performed with the novel ERCC1-antibody clone 4F9. The relationship between ERCC1 expression and clinicopathological parameters, as well as best objective response to therapy and progression-free survival (PFS) during PBC was evaluated.
High ERCC1 expression was observed in 66% of ACC samples. During PBC, 43 patients experienced objective response (29.5%), 49 stable disease (33.6%), 8 mixed response (5.5%) and 46 progressive disease (31.5%) without any relationship with the ERCC1 immunostaining. No significant correlation was also found between ERCC1 expression and progression-free survival (median 6.5 vs 6 months, P = 0.33, HR = 1.23, 95% CI = 0.82–2.0).
ERCC1 expression is not directly associated with sensitivity to PBC in ACC. Thus, other predictive biomarkers are required to support treatment decisions in patients with ACC.