Make a mistake on stock and it is like a cancer?

Someone commented: "Make a mistake on stock and it is like a cancer...it will suck you slowly."

If it is true that stock is somehow cancer-like, then diversification of stocks across sectors in your portfolio will help to reduce the cancer rate and prevent getting suck too often.

     One stock: Probability of getting a cancerous stock: 0 - 100%
   Two stocks: Probability of getting a cancerous stock: 25 - 50%
Three stocks: Probability of getting a cancerous stock: 11.1 - 33.3%