Colorectal cancer (CRC), prostate cancer (PrC), and gastric cancer (GC) are common worldwide where genetics play a big role. We have previously shown that in families with more than one case of CRC, the risk of the other malignancies is increased. Furthermore, we have several loci, among others 6q25 loci to be involved in the developing of this cancer syndromes involving CRC combined with PrC and/or GC (Wallander, Genes Chromosomes Cancer 2019). Here, we will do a whole-genome sequencing of 85 patients from 85 families with CRC, PrC, and GC. Regions identified in our previous study (Wallander, Genes Chromosomes Cancer 2019) will be analysed, as well as new variants that could could contribute to this syndrome. In our group we have previously analysed patients in families with CRC incidents only and will variants identified in that cohort be used as a comparison to variants identified in the novel cancer syndrome.