I'd like to analyze the data in patient samples. I tried searching in GEO database by typing in some key words, however, no relevant studies come out. Is there any other database that I can find for human samples??
you can find many datasets in GEO by searching "homo sapiens" or by searching a keyword like "Cancer" and adding a filter like "homo sapiens" in "organism" field.
If that didn't work for you, links in other answers may be helpful.