Mutations in the drug binding region of BCR-ABL lead to imatinib resistance during the management of chronic myeloid leukemia (CML). In our study, 62 Philadelphia positive (Ph+) CML patients showing conspicuous expression of BCR-ABL gene were treated with imatinib. At the end of 3 months, 21/62 (33.87%) patients did not obtain complete hematological response (CHR) and also showed no significant decrease in BCR-ABL gene expression. In all the imatinib-resistant patients BCR-ABL gene was PCR amplified and sequenced. The sequence analysis showed four novel missense mutations p.(Leu301Ile), p.(Tyr320His), p.(Glu373Asp), p.(Asp381Asn) and six already reported mutations p.(Val256Gly), p.(Thr315Ile), p.(Gly250Glu), p.(Tyr253His), p.(Phe317Leu), p.(Met351Thr) which contributed in the formation of inactive enzyme and also two novel frameshift mutations p.(Glu281*) and p.(Tyr393*), which resulted in truncated protein formation. Further, the structural analysis revealed all these mutations affected P-loop, gatekeeper, catalytic and activation loop domain regions of the enzyme causing poor imatinib binding in the ATP region. The primary intention of the study was to find out the mutations in the BCR-ABL gene causing imatinib resistance. This study highlights the need for BCR-ABL gene sequence analysis to detect the mutations in CML patients in order to properly guide the therapy.

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Osteocytic potentiality of human CD34 stem cells explored in the present study by generating in vitro agarose gel 3D model to understand the bone ossification process. The G-CSF and IL-3 mobilized human CD34 stem cells isolated apheretically from donor peripheral blood and purity of the cells was assessed by FACS and immunocytochemical (ICC) studies. The CD34 stem cells were cultured in gel based 3D model with osteogenic stimulating medium for 21 days. The transition stages from undifferentiated to differentiated osteocytes through osteoblasts were studied with expression markers Differentiated cells at Day 7 showed positive reactivity with monoclonal anti-Runx2, an early osteoblastic marker. qPCR expression analysis showed early and mature osteoblastic markers like RUNX2, Osterix, RANKL, along with osteocyte markers SPARC, Sclerostin. While poor expression of OSCAR genes was observed apart from conspicuous expression of alkaline phosphatase. The expression of sclerostin and SPARC suggests that these differentiated cells are behaving like true osteocytes, sclerostin expression causes transformation of osteoblast into osteocytes and negligible expression of OSCAR, RANK, NFATc and cathepsin K genes explains there are no osteoclasts in the differentiated culture. These cells showed positive reaction with Alizarin red stain indicating expression of calcium bound bone morphogenic proteins like osteonectin. All these results clearly confirm the human CD34 stem cells possess unique osteogenic differentiation potential and can be used in the early regeneration of injured bone.

The successful differentiation of human CD34(+) stem cells into type-II pneumocytes, and transplantation of such cells obtained from the patient's stem cell could be the futuristic approach to regenerate diseased lung alveoli.

In the present study, in vitro differentiation of stem cells with retinoic acid induction may result in the formation of astrocytes.