HP and idiopathic pulmonary fibrosis: PCA plots using the differentially expressed genes between selected non-UIP subtypes and UIP samples showed that the specific non-UIP pathology subtypes tend to be well-separated from UIP samples for subtypes such as RB and HP (See Additional file 1: Figures S4A, C), while other non-UIP samples may be interspersed with UIP samples (See Additional file 1: Figures S4B, E).