B cell growth, differentiation and malignancies

The primary function of a B cell (or lymphocyte) is to produce large quantity of secreted immunoglobulin (also known as antibody) to fight against bacteria, viruses and other foreign insults to the human body. Each B cell makes only one distinct immunoglobulin which recognizes a cognate antigen. It is estimated that B cells in the human body can produce as many as 10¹¹ different antibodies. Thus, each B cell must undergo a series of differentiation, selection and maturation processes before it is endowed with the ability to produce a functional immunoglobulin to represent in the large and diverse antibody repertoire. While insufficient B cells and insufficient antibody production can thus lead to infections, uncontrolled growth of B cells can lead to leukemia and lymphoma. In this article, we will focus on transcription factors and signaling molecules that involve in normal B cell development and differentiation. These molecules, when mutated or not tightly regulated, will contribute the formation of B cell malignancies.