Comprehensive transcriptomic analysis of cell lines as models of primary tumors across 22 tumor types.

Cancer cell lines are a cornerstone of cancer research but previous studies have shown that not all cell lines are equal in their ability to model primary tumors. Here we present a comprehensive pan-cancer analysis utilizing transcriptomic profiles from The Cancer Genome Atlas and the Cancer Cell Line Encyclopedia to evaluate cell lines as models of primary tumors across 22 tumor types. We perform correlation analysis and gene set enrichment analysis to understand the differences between cell lines and primary tumors. Additionally, we classify cell lines into tumor subtypes in 9 tumor types. We present our pancreatic cancer results as a case study and find that the commonly used cell line MIA PaCa-2 is transcriptionally unrepresentative of primary pancreatic adenocarcinomas. Lastly, we propose a new cell line panel, the TCGA-110-CL, for pan-cancer studies. This study provides a resource to help researchers select more representative cell line models.

Popliteal vein compression due to popliteal artery aneurysm: effects of aneurysm size.

Unlike the venous compression associated with larger popliteal artery aneurysms, which frequently is associated with deep vein thrombosis, the venous compression caused by the moderate sized (greater than 2 cm and less than 3 cm) aneurysms in the reported cases is not associated with thrombosis. The extrinsic compressive effect of these moderate sized popliteal artery aneurysms on the adjacent vein is shown to vary with the patient's leg position. Three of the four patients with unilateral leg swelling discussed here had bilateral popliteal artery aneurysms. In these cases, the contralateral leg had a small popliteal aneurysm (less than 2 cm) and no leg swelling was present. The cases suggest that popliteal artery aneurysm size is an important factor in determining the type of venous obstruction that results from the extrinsic compression of the ipsilateral popliteal vein. The described phenomenon of a popliteal artery aneurysm having the effect of restricting flow in the ipsilateral popliteal vein must be included as a differential diagnosis among the causes of unilateral leg swelling in the absence of deep vein thrombosis.