Decreased expression of the human immunoglobulin J-chain gene in squamous cell cancer and adenocarcinoma of the lungs

Secreted polymeric immunoglobulins, IgA dimers and IgM pentamers, are unique in having not only the L and H chains but also the J chain, which is responsible for oligomerization. These antibodies belong to the local adaptive immune system, located in the mucosas of the respiratory and digestive systems and acting first to protect the body from infectious agents. Polymeric immunoglobulins are produced by highly specific B cells and are actively transported to the mucosa surface through epithelial cells. Hence, their production and, accordingly, the J-chain content are associated with the transporting function of the epithelium and depend on its state, which dramatically changes upon malignant transformation. The content of the J chain and the transcription level of its gene were studied in normal and tumor cells at various stages of squamous cell cancer and adenocarcinoma of the lungs by RT-PCR and immunoblotting.