[The significance of expression of isoforms RARa1 and RARa2 in response to medicinal therapy and in evaluation of total survival of patients with primarily detected multiple myeloma].

Introduction: The RARa is a transcription factor playing important role in such processes as proliferation, differentiation and apoptosis of cells in norm and in tumor. At the same time, it is little known about significance of expression of two major products of transcription of gene RARa - isoforms RARa and RARa - in pathogenesis of solid and non-solid tumors, including multiple myeloma. The actual data testify ambiguity of input made by isoforms RARa and RARa into processes of tumor development and progression of malignant tumors.

The Results: It was established that higher level of expression of isoform RARa in combination with increased expression of isoform RARβ (group 1) statistically reliable associated with lesser decreasing of concentration of Bence Jones protein in urine of patients in the result of applied treatment and, therefore, lesser effectiveness of response to standard treatment according protocol M-2 in comparison with group II which included patients with lesser levels of expression of RARa and RARβ (32.8% and 62.8% for groups I and II correspondingly; p=0.037). The analysis of indices of survival of examined patients in groups I and II demonstrated that median of total survival of patients from group I was reliably lower than in patients included into group II (30 and 84 correspondingly; p=0.046).

Conclusion: The results of study demonstrate that increased level of expression in the first instance of isoform RARa in combination with hyper-expression of isoform RARβ but not RARa can have unfavorable significance in case of evaluation of response to medicinal therapy and prognosis of total survival in patients with multiple melanoma.