Pulmonary surfactant is primarily responsible for lowering the surface tension at the air-liquid interface in the alveoli, a process that is essential for normal respiration. Pulmonary surfactant is a mixture of phospholipids and proteins, including four distinct surfactant-associated proteins (SPs): SP-A, SP-B, SP-C, and SP-D. SP-B and SP-C showed strong immunohistochemical expression in Lung Hyperplasias and Adenomas, suggesting that SP-B and SP-C are related to lung tumorigenesis. SP-A and SP-D are large multimeric proteins belonging to the family of calcium-dependent lectins, designated Collectins, which contribute to the innate immune system. SP-D is a protein encoded by the SFTPD gene. Studies found low expression of SF-D expression in lung, gastric, and breast cancers and high expression in different stages and grades of ovarian cancer. SF-D expression could be associated with a favorable prognosis in lung cancer but unfavorable in non-pulmonary sites such as breast, gastric and

STAT1/ISGF3 [EPR21057-141]

STAT1 (signal transducer and activator of transcription 1) or ISGF3 is involved in upregulating genes due to a signal by either type I, type II, or type III interferons. STAT1 may be a target for therapeutic treatment to restore apoptotic mechanisms and sensitivity to chemotherapy. The phosphorylated STATs dimerize, associate with ISGF3G/IRF-9 to form a complex termed ISGF3 transcription factor, that enters the nucleus. ISGF3 binds to the IFN stimulated response element (ISRE) to activate the transcription of interferon stimulated genes, which drive the cell in an antiviral state. The phosphorylated STAT1 is a potential predictor of interferon (IFN) response for advanced renal cell carcinoma. Mutations in the gene is associated with death at an early age due to overwhelming viral infection (complete STAT1 deficiency.

STAT1/ISGF3 [EPR21057-141]