Cancer is characterized by the uncontrolled growth and spread of abnormal cells in the body. At its core, the condition arises from genetic mutations that disrupt the normal cell cycle regulation, allowing cells to divide independently of controlling signals. This uncontrolled proliferation can lead to the formation of tumors, which are masses of abnormal tissue. If left unchecked, these cells can invade nearby tissues and spread through the circulatory and lymphatic systems, a process known as metastasis. Diagnosis and study involve understanding the complex interplay of cellular genetics, environmental factors, and internal mechanisms that lead to malignant transformation.