Аннотация:Disseminated tumor cells (DTCs) in the bone marrow (BM) have been shown to be precursors todistant metastases. The discovery of DTCs in non-small cell lung cancer (NSCLC) will provide crucialinformation of the features of metastasis. As well as the potential for discovering new targets forNSCLC treatment. The goal of the study is to see if DTC can be detected in BM and to determine theincidence of BM involvement in NSCLC patients, as well as their impact on the BM lymphocytepopulation. Morphological and immunological approaches were used to examine 62 bone marrowsamples from NSCLC patients. DTCs analysis was performed using flow cytometry (FACS Canto II,the USA, Kaluza Analysis v2.1 software), monoclonal antibodies to CD45, EPCAM, CD133,lymphocyte populations CD3, CD4, CD8, CD19, CD20, CD16, CD27, directly labeled with variousfluorochromes were used. The EPCAM+CD45- (DTCs) in the BM were found in 43.5% of patients(threshold level: 1 cell per 10 million myelocaricytes). The CD133+EPCAM+CD45-cells were found in33,3% (9/27) cases. The presence of DTCs did not correlate with tumor size, lymph node status, ortumor stage. DTCs were detected at the highest rates in stages IA and IIA: 60.7 percent and 58.3percent, respectively. In adenocarcinoma, BM involvement was found in 45 percent of cases, while insquamous cell carcinoma, it was found in 37 percent of samples (p = 0.501). DTCs were observed tobe more in highly differentiated tumors (p = 0.023). There are no significant connections between thepresence of DTCs in the BM and myelogram parameters. A decrease in the number of granulocyticlineage cells was observed in 4% of BM involvement (p = 0.036). A significant increase in the level ofsubpopulations of CD16+CD4-NK-cells (p = 0.002), CD27+CD3+ T-cells (p = 0.015) with BM damagewas revealed.Conclusion: It has been proven that DTCs can be detected in the BM of NSCLC patients. BMinvolvement was identified in 43.5% cases. Even in the early stages of NSCLC, DTCs are found.There was a link discovered between BM involvement and the degree of tumor differentiation.Adenocarcinoma of the lung had a higher rate of BM involvement than squamous cell carcinoma of thelung. A relationship between DTCs and BM lymphocyte populations was revealed: subpopulations ofCD16+CD4-, CD27+CD3+.