Nodules

Nodules are localized, often spherical anatomical or pathological structures that form within various tissues and organs. In clinical medicine, they are most commonly identified as lung, thyroid, or rheumatoid nodules and can be benign (inflammatory) or malignant (cancerous) [20, 23]. While 'nodules' are not specific molecular targets themselves, they serve as critical diagnostic and therapeutic endpoints; for example, the regression of rheumatoid nodules is a key indicator of efficacy for Janus kinase (JAK) inhibitors such as tofacitinib [4]. In oncology, the detection and molecular profiling of nodules (e.g., identifying BRAF or RET mutations in thyroid nodules) guide the administration of targeted tyrosine kinase inhibitors [1, 3]. In plant biology, root nodules are specialized organs formed through symbiotic interactions with nitrogen-fixing bacteria, involving specific signaling molecules called nodulins and nodulation receptor kinases [10, 11, 13]. Because the term describes a macroscopic or microscopic structure rather than a discrete protein or receptor, it is not considered a molecular therapeutic target in the traditional sense [1, 23].

Other names

Anatomical nodulesClinical nodulesPathological nodulesPulmonary nodulesThyroid nodulesRheumatoid nodulesRoot nodulesMeiotic nodulesActin nodules

Nodules are physical structures and not molecular targets; however, drugs targeting molecules within them (e.g., kinases or cytokines) can lead to nodule regression or are used for targeted imaging [4, 8, 12].