Tertiary lymphoid structures (TLS) are de novo lymphoid formations that are induced within tissues during inflammatory episodes. TLS have been reported at various anatomic sites and in many different contexts like cancer, infections, autoimmunity, graft rejection, and idiopathic diseases. These inducible, ectopic, and transient lymphoid structures exhibit the prototypical architecture found within secondary lymphoid organs (SLO) and have been recently appreciated as a major driver of the local adaptive immune reaction. As TLS emerge within tissues, the isolation in situ and the molecular characterization of these structures are challenging to operate. Laser capture microdissection (LCM) is a powerful tool to isolate selective structural components and cells from frozen or paraffin-embedded tissues. We and other groups previously applied LCM to decipher the molecular network within TLS and uncover their intrinsic connection with the local microenvironment. In this chapter, we describe a detailed LCM method for selecting and isolating TLS in situ to perform comprehensive downstream molecular analyses.
Keywords: Frozen tissue; Gene expression profiling; Laser capture microdissection; Lung cancer; Lymphocyte; RNA analysis; Tertiary lymphoid structure.