P049 Defining the tumor origin in lung post-transplant recipient using HLA typing
Here we present a case to show that HLA typing can be used to identify tumor origin in transplant recipients. A 61-year-old man with a past medical history of idiopathic pulmonary fibrosis received right lung transplant on 7/25/2016. He was admitted to the hospital on 12/25/17 with complaints of worsening shortness of breath as well as a non-productive cough and wheezing for a few days prior to arrival. Examination of the lungs revealed a poorly differentiated adenocarcinoma involving the right lung. The patient’s left lung had metastatic adenocarcinoma, interstitial fibrosis, fibroblastic foci, and interstitial chronic inflammation. There was also metastatic tumor identified in the liver, vertebrae, adherent to the adventitia of the aorta, esophageal, and gastric serosa. The patient expired 548 days post-transplant. After the finding of cancer in the donor’s lung was reported to UNOS, other centers that shared this donor requested additional testing on cancer to determine if it was donor-derived cancer. HLA typing performed on DNA isolated from the formalin-fixed paraffin-embedded tumor tissue sample fully matched the patient’s original HLA typing. This finding indicated that tumor did not arise from the donor’s lung. This case shows that HLA typing can be used to identify an origin of malignant tumor developed in transplant recipients, in particular, when no fresh tissue or DNA from both donor and recipient is available for microsatellite analysis.