Li and colleagues have similarly witnessed attenuation of PTHR1 mRNA and protein expression in osteosarcoma cells incubated with β‐alanine, indicating its positive relation with tumour invasion and metastasis38; and upon incubating Saos‐2 and U2OS human osteosarcoma cell lines in β‐alanine, Wen et al found expression levels of MMP‐2 and MMP‐9 mRNA notably reduced, whereas tissue inhibitors of metalloproteinase (TIMP)‐1 and TIMP‐2 were expressed at high levels. Here, MMP9 is linked to osteosarcoma.