Probably gene expression omnibus (GEO) would be a good place to start because most of the published studies deposit their data there. For example, GSE14333 is one of the highly cited datasets for CRC that is available in GEO. There are many papers that have used this datasets to create biomarkers, which can stratify CRC patients. For the TCGA, one of the simplest methods is using the UCSC cancer genome browser to download the data. UCSC xena also has a nice visualisation tools that can be handy.

thanks Pawan,

its a valuable answer, but truly i need biological tests like Bilirubin, ALP, Complete blood count, and rest of normal biological marker rather than genetic marker,

I already use both but I am not familiar with how can i get clinical data from any of the previously mentioned websites

many thanks