I asked this on the other board but didn't get a r

I asked this on the other board but didn't get a response so I figured I'd try here... Does anyone know if the cohorts in this study all have the same type of cancer or is it only stage four "cancer" that they are looking for?

It seems like they'd want to keep the cohorts as similar as possible to reduce the variables but I thought I'd ask those who know more than I do.