First step is to define your biological question: Why are you doing GO analysis in the first place? What do you hope to gain from it? Do you have a hypothesis?

Also, it's difficult for us to answer when we have no idea what you actually did. Did you do whole genome sequencing, microarray, ChIP-Seq, RNA-seq, single-cell RNA-seq, etc.?

Doing bulk RNA-seq followed by GO and finding that proliferation genes get upregulated in cancer isn't going to tell you anything new.

Try to define a question that's interesting and novel; e.g. are there genes that consistently go up in subtype A of cancer but go down in subtype B of cancer.

There are plenty of papers that demonstrate how to do good data science with cancer data (e.g. https://pubmed.ncbi.nlm.nih.gov/31287989 ).