In human body, the cell growth and differentiation are highly controlled and regulated, but in cancer cells

In the human body, cell growth and differentiation are strictly regulated by feedback mechanisms and genetic instructions to maintain homeostasis [3]. Cancer arises when these regulatory mechanisms break down due to genetic alterations in critical genes, such as oncogenes and tumor suppressor genes [3]. This breakdown leads to unchecked cell division and a progressive loss of differentiation [1]. Unlike normal cells that grow and multiply only as needed, cancer cells grow and divide uncontrollably, failing to balance division with cell death [3]. This unregulated proliferation results in the formation of tumors, which are classified as benign if they remain localized or malignant if they acquire the ability to invade nearby tissues and metastasize to distant organs [4]. Consequently, the fundamental characteristic of cancer is the failure of the body's orderly control systems, leading to abnormal tissue masses [3].

Sources

1. [2] https://www.iarc.who.int/wp-content/uploads/2018/07/wcr-3.pdf
2. [3] https://www.cancer.gov/about-cancer/understanding/what-is-cancer
3. [1] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > Do You Know? > p. 111
4. [4] https://www.nature.com/scitable/topicpage/cell-cycle-control-by-oncogenes-and-tumor-14191459/