FAP and neoplasm: Comparison to the clinical samples indicated that the obtained multi‐spheroid models closely resemble the initial or later stages of metastatic tumors in terms of tumor structures and FAP expression.[47] Extended culturing of mouse prostate metastasis cell lines with or without Aldh1a3 gene knockdown, followed by comparison with mouse metastasis models, demonstrated that our in vitro model closely mirrors in vivo conditions, providing a valuable platform for further investigation into the mechanisms of prostate cancer metastasis.