In this review, we discuss about the cross-interactions of Aβ1-42 with other amyloids, which have been presented either as integrated part of Aβ1-42 neurotoxicity process (such as Tau) or conversely with a preventive role in AD pathogenesis by directly binding to Aβ (such as transthyretin, cystatin C and apolipoprotein A1), Figure 1. The gene discussed is CST3; the disease is Alzheimer disease.