Having pancreatic cancer with tumoral loss of ATM and normal TP53 protein expression is associated with a poorer prognosis.

PURPOSE: To determine how often loss of ataxia-telangiectasia-mutated (ATM) protein expression occurs in primary pancreatic ductal adenocarcinomas and to determine its prognostic significance. EXPERIMENTAL
DESIGN: The expression of ATM and TP53 was determined by immunohistochemistry in 397 surgically resected pancreatic ductal adenocarcinomas (Hopkins; Johns Hopkins Medical Institutions, Baltimore, MD), a second set of 159 cases (Emory; Emory University Hospital, Atlanta, GA), and 21 cancers after neoadjuvant chemoradiotherapy. Expression was correlated with the clinicopathologic parameters, including survival.
RESULTS: Tumoral ATM loss was observed in one cancer known to have biallelic inactivation of ATM and 50 of the first 396 (12.8%) cases, significantly more often in patients with a family history of pancreatic cancer (12/49; 24.5%) than in those without (38/347; 11.0%; P = 0.019). In the Hopkins series, ATM loss was associated with a significantly decreased overall survival in patients whose cancers had normal TP53 expression (P = 0.019) and was a significant independent predictor of decreased overall survival (P = 0.014). Seventeen (10.7%) of 159 Emory cases had tumoral ATM loss and tumoral ATM loss/normal TP53 was associated with poorer overall survival (P = 0.1). Multivariate analysis of the combined Hopkins/Emory cases found that tumoral ATM loss/normal TP53 was an independent predictor of decreased overall survival [HR = 2.61; confidence interval (CI), 1.27-5.37; P = 0.009]. Of 21 cancers examined after neoadjuvant chemoradiotherapy, one had tumoral loss of ATM; it had no histologic evidence of tumor response.
CONCLUSIONS: Tumoral loss of ATM protein was detected more often in patients with a family history of pancreatic cancer than in those without. Patients whose pancreatic cancers had loss of ATM but normal TP53 had worse overall survival after pancreatic resection. ©2014 AACR.