Doxycycline is a broad-spectrum antimicrobial agent used in clinical for a long time. In recent years, many studies showed that its pharmacological activities of anti-tumor, heart function improvement, nerve protection and antiasthma depended on its inhibition of matrix metalloproteinase ( MMPs) . In the present paper,the new pharmacological actions of doxycycline were reviewed to promote the applications in clinics.

Objective:To improve the understanding of chronic lymphoblastic leukemia (CLL) with t(14;18)(q32;q21).Methods:The clinical data of 3 cases diagnosed as CLL with t(14;18)(q32;q21) in the Tianjin KingMed Medical Laboratory from January 2020 to January 2021 were retrospectively analyzed. The clinicopathological data, morphological examination, immunophenotype, cytogenetics and somatic mutation of immunoglobulin heavy chain variable region genes of patients were comprehensively analyzed, and the literature was reviewed.Results:All the 3 patients showed lymphatic proliferative diseases, and their morphological characteristics and immunophenotype were typical characteristics of CLL.Conclusions:The diagnosis of CLL is mainly based on the typical morphology and immunophenotype of tumor cells. The presence of t(14;18) should not be used to exclude the diagnosis of CLL.