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Everything You Need To Know About Cancer

Cancer refers to a collection of related diseases characterized by cells dividing uncontrollably and spreading into surrounding tissues. This can occur almost anywhere in the body and often occurs in the form of growths called tumors. 

Differences Between Cancer Cells And Normal Cells

Cancer cells usually have more genetic changes and mutations in DNA compared to normal cells and are less specialized as they tend to continue dividing and don’t mature into distinct cell types. Additionally, cancer cells tend to ignore signals from a process known as apoptosis, which is used for programmed cell death. They are also, at times, able to influence normal cells in the area surrounding a tumor which can lead to the formation of blood vessels that supply tumors with oxygen and nutrients and remove waste products. 

How Cancer Arises

Cancer is caused primarily due to changes to genes that control cellular function, specifically their growth and reproduction. While some genetic precursors for cancer are inherited, they are often caused due to damage to the DNA due to environmental factors. These include certain substances called carcinogens, radiation, and excess exposure to ultraviolet rays from the sun.

Drivers Of Cancer

There are three main types of genetic changes or “Drivers” of Cancer:
  • Proto-oncogenes: These are responsible for normal cell growth and lead to cancer when they become altered or overactive.
  • Tumor suppressor genes: These genes control cell growth and alterations in them may lead to uncontrolled cellular division.
  • DNA repair genes: These help fix damaged DNA and mutations in these tend to lead to additional mutations that may lead to the development of cancer.

How Does Cancer Spread

During metastasis, cancer cells move through the blood or lymph system, forming new tumors (metastatic tumors) in different parts of the body. These metastatic cancer cells tend to share molecular features with the primary cancer cells and tend to be of the same type.

Types Of Cancer

With over 100 types of cancers, they are usually characterized based on where they originate such as lung, or brain cancer. They may also be described based on the type of cell that created them. Some common categories of cancers that originate in specific types of cells include Carcinoma which is formed by epithelial cells, Squamous cell carcinoma which is formed in squamous cells, and Sarcomas which form in soft tissues, etc.