Profile of fibrosis-related gene transcripts and megakaryocytic changes in the bone marrow of myelodysplastic syndromes with fibrosis.

Bone marrow fibrosis (MF) in myelodysplastic syndromes (MDS) is associated with an adverse prognosis. It is likely that molecular changes similar to those in primary myelofibrosis (PMF) lead to MDS-MF, but gene expression profiling has not yet been carried out. We analysed bone marrow biopsy samples by PCR, qPCR (45 transcripts per sample), and immunohistochemistry from MDS patients with fibrosis (n = 70/119; including 19/70 MF0 > MF follow-up cases), MDS without fibrosis (n = 49/119), and 33 controls. SRSF2 and JAK2 mutations were detectable in up to 13% including 3/19 follow-up cases with evidence of clonal evolution during MF progression. MDS-MF showed increased expression of thrombospondin 1 (THBS1), TIMP metallopeptidase inhibitor 1 (TIMP1), transforming growth factor beta 1 (TGFB1), matrix metallopeptidases 2 and 14 (MMP2, MMP14), SMAD family members 3 and 4 (SMAD3, SMAD4), and miR-146b. Paralleling MF progression, a subfraction of follow-up cases showed megakaryocytic changes with increased CD42b+ pro-platelet deposition in the bone marrow. In summary, fibrosis in MDS-MF and PMF shows many molecular and morphological similarities.