In RA, overexpression of miR-99b-5p inhibits the RASSF4 expression, leading to a reduced T cell apoptosis rate and an increased proliferative index, and promotes the secretion of pro-inflammatory factors such as IL-2, IL-6, TNF-α, and IFN-γ, ultimately exacerbating joint inflammatory responses. The gene discussed is RASSF4; the disease is rheumatoid arthritis.