Abstract: A method or process for the diagnosis/prognosis/follow-up of cancer in vertebrates, comprising the following steps: i) extracting nucleic material from a biological sample; ii) using at least one pair of amplification primers in order to obtain amplicons of at least one target sequence; iii) using at least one detection probe for detecting the presence of the said amplicons; characterised in that the extraction step is carried out from extracellular nucleic material from a biological sample. More precisely, the said nucleic material is RNA or DNA of the CA9 gene circulating in the free state in a biological sample. The invention also relates to the pairs of amplification primers and/or a detection probe for the diagnosis/prognosis/follow-up of cancer including at least 15 nucleotide patterns of a nucleotide sequence selected from the SEQ ID nos. 1 to 6, and a kit including the said at least one pair of primers and/or at least the said probe.