Abstract: The invention relates to a method for diagnosing a cancer in a mammal in a need thereof. The method comprises the following steps: collecting a biological sample from said mammal; determining, from said biological sample, if the ADAMTSL5 gene is overexpressed; diagnosing a cancer from the determination of the overexpression of said gene. It also relates to a kit for determining an overexpression of the ADAMTSL5 gene in a biological sample obtained from a mammal, to a pharmaceutical composition comprising an agent targeting ADAMTSL5 or the ADAMTSL5 pathway as well as a pharmaceutically acceptable carrier for use in the treatment of a cancer, and to a use of an ADAMTSL5 mRNA or protein as a biomarker of cancer.