...a 50 year-old white male who presented with fevers and night sweats...He was found to have a 4 cm tumor in his liver determined to be a poorly differentiated intrahepatic cholangiocarcinoma…allele specific expression of the mutated allele from the same tissue specimen suggests nearly complete loss of function of ERRFI1 in this patient's tumor....the patient was treated with erlotinib 150 mg orally/daily...After 3 months, RECIST v1.1 partial response evidenced by a decrease of 58% in the sum of largest diameters was observed...