NRG1 and cancer: Cancer-associated fibroblasts (CAF) are divided into five subclusters: ACTA2 with markers ATAC2, MYH11, and TAGLN; OGN with markers CLU, NEAT1, BASP1, GADD45G, GAS1, and OGN; OGN/P16 with markers CLU, NEAT1, BASP1, GADD45G, GAS1, OGN, and P16; IGF1 with markers COL1A1, COL1A2, DCN, IGF1, APOD, ABCA8, and NRG1; and MKI67 with MKI67, F3 markers (Fig. 5A and B).