The number of lncRNAs that were not expressed (or not detected using the poly-A selection method) and expressed in liver. An lncRNA is considered to be expressed in liver if the average FPKM is above 1 in at least one exposure group (corn oil, PCN, or TCPOBOP). Among the liver-expressed lncRNAs, the percentages of lncRNAs that were not differentially regulated, increased, or decreased by chemical exposure were calculated and displayed as two pie charts (PCN and TCPOBOP). Differential expression was considered at P < 0.05 (Cuffdiff).