Caveolin-1 (CAV1), a membrane-associated scaffolding protein, that acts both as a tumor suppressor and a promoter of metastasis depending on the type of cancer and stage (Campos et al., 2019; Simon et al., 2020), is enriched in MAMs (Sala-Vila et al., 2016; Bravo-Sagua et al., 2019; Figure 1). Here, CAV1 is linked to cancer.