What 5 signs of cancer in early 20 year old?

Can't say: There are different cancers and they all have different signs and symptoms. Your question is pretty broad. The only symptom that might be seen in all types of cancer is fatigue. But that is seen in many many non cancer diagnoses too.

That question is: not answerable. There are many types of cancers that can occur, and cancer can arise in almost any part of the body, so any symptoms would be related to the type, location, and extent of the cancer. Constitutional symptoms like fatigue or weight loss can also be seen in many non cancerous conditions.