ABCA1 and neoplasm: These IHC findings highlight the heterogeneous expression patterns of ABCA1 across different cancers, suggesting its potential role in tumour progression and malignancy-specific regulatory mechanisms; for example, ABCA1 is involved in cholesterol efflux, and differences in ABCA1 expression can affect cholesterol metabolism and HDL biosynthesis; provide nutrients and signalling molecules required for tumour cells to grow; and subsequently affect tumour cell proliferation, invasion and metastasis.