LNK expression, subcellular localisation and survival associations in breast, cervical and colorectal cancer

The role of lymphocyte adaptor protein (LNK) in breast, cervical and colorectal cancer remains incompletely characterised. We examined LNK expression, subcellular localisation and associations with survival across these cancers. Gene Expression Profiling Interactive Analysis and cBioPortal were used to assess LNK messenger ribonucleic acid (mRNA) expression, while Kaplan-Meier Plotter was used for exploratory survival analyses. Western blotting and quantitative confocal immunofluorescence assessed protein expression and localisation in 12 cancer cell lines and three non-tumoural controls. LNK mRNA expression varied among tumour subtypes and was significantly lower in cervical tumours than in adjacent normal tissue. Higher expression was associated with longer overall and recurrence-free survival in triple-negative breast cancer but shorter survival for both endpoints in colorectal cancer; no significant associations were observed in cervical cancer. LNK was detected in the nucleus and cytoplasm of all cancer cell lines. Significant nuclear predominance was observed in one of four triple-negative breast cancer cell lines and three of four cervical cancer cell lines, whereas their non-tumoural controls showed cytoplasmic predominance. Colorectal cancer cell lines displayed heterogeneous subcellular distributions. These exploratory findings suggest cancer type-specific associations between LNK expression and survival that require independent validation, while nuclear localisation warrants investigation of potential nuclear functions.