ELK1 and cholangiocarcinoma: After a combined analyses of the above results, we found that only ETS Proto-Oncogene 1 (ETS-1) and ELK-1 fulfilled the criteria of Z score <–1 in two CCA cell lines, suggesting that ETS-1 and ELK-1 were the most likely transcription factors activating MALT1 expression in these cells (Table 1).