The gut-associated lymphoid tissue represents an integral part of the immune system. Among the powerful players of the mucosa-associated lymphoid tissue are isolated lymphoid structures (ILSs).
Additionally, in the course of cancer, ectopic lymphoid structures (ELSs; also known as tertiary lymphoid structures, TLSs) were shown to be formed at the tumor site. Both ILSs and ELSs act as multitasking information centers triggering multifaceted immune responses.
An in-depth understanding of the complexity and functionality of ILSs and ELSs may lead to new directions in therapeutic interventions and/or provide help in treatment decisions as part of personalized medicine.