Q.Describe the main differences between a normal cell and a cancer cell, and explain the common methods used to detect and diagnose cancer.

Normal cells versus cancer cells: In a healthy body, cell division is tightly regulated — cells divide only when new cells are genuinely needed, for growth or to replace damaged tissue, and stop dividing once that need is met. Cancer cells lose this regulation entirely: they continue dividing relentlessly, ignoring the normal signals that would otherwise slow or stop them, producing a mass of abnormal tissue called a tumour.

Benign versus malignant: Not every tumour is cancerous in the medical sense. A benign tumour grows locally, remains confined within a capsule of tissue, and does not invade or spread elsewhere. A malignant tumour — the correct meaning of "cancer" — grows aggressively, invades and damages surrounding normal tissue, and can send cells into the blood or lymphatic system that travel to and establish new tumours in distant organs, a process called metastasis. It is this invasive, spreading behaviour that makes malignant tumours dangerous, while benign tumours, though they may still need treatment, generally are not. …

Separate the answer into the three parts the question explicitly asks for — normal-versus-cancer-cell behaviour, benign-versus-malignant d …

Do not treat 'tumour' and 'cancer' as synonyms — a tumour is simply an abnormal mass of tissue, and only a malignant tumour is p …