Nestin is a protein belonging to class VI of intermediate filaments (IF). This protein is found in neural progenitor cells during the formation of both the central and peripheral nervous systems. Usually, anti-nestin staining in the cytoplasm is seen primarily in disease states. Research has shown that nestin expression rises significantly in melanoma and is linked to more severe stages of the illness. Nestin immunoreactivity has also been observed in HMB-45-negative amelanotic and melanotic, non-desmoplastic melanoma cells. Additionally, nestin serves a role in the subclassification of breast carcinoma. Only cytoplasmic staining is regarded as positive, while nuclear staining is viewed as an insignificant artifact.