Cancer Basics

This section breaks down cancer into its constituent parts.

What is cancer?

Simply defined, cancer constitutes the uncontrolled proliferation, or growth, of abnormal cells.  These so-called renegade cells operate unchecked and the accumulation leads to disease.  The origins of these renegade cells are diverse but ultimately result in alterations and/or mutations in the genetic makeup of the cell.  Over the course of cancer progression, also referred as tumorigenesis, cancer cells acquire certain common characteristics, aberrations in their cellular functions such as enhanced proliferation, ability to replicate limitlessly, reduced cell death, and increased migration and invasion into surrounding tissues, among others. 

What is a cell?

A cell is the functioning unit of the human body.  One can visualize the human body like an ecosystem whose constituent parts each contribute to its functionality.  Each human, the organism, is composed of various organs and tissues including the colon, prostate, breast, and lung etc.  Cells with similar genetic backgrounds make up each organ.  Therefore, we have breast cells, lung cells, colon cells etc, each of which possess intrinsic similarities and differences.  In its entirety, the human body possesses more than a trillion cells!  Fortunately for us, most of the time, all trillion cells cooperate to produce a viable, functioning, being. 

What is a protein?

Inside each of these cells are proteins: the do-ers, the movers and shakers of cellular function.  Through interactions and modifications of neighbouring proteins in the cell, the cell divides, migrates, dies, performs a function.  Numerous interactions couple together in a signaling pathway to elicit specific functions.  These processes are essential for maintaining homeostasis, but when proteins act in an uncontrolled manner, disease arises.  In the cancer field, proteins can be classified as oncogenes (drivers of cancer) or tumor suppressors (cancer brakes).  However, the complexity of protein networks suggests that proteins serve multiple functions and thus, may possess both tumor suppressive and oncogenic functions.  

What is a gene?

The concept of DNA (deoxyribonucleic acid) is familiar to most.  It is the genetic make-up behind every organism.  To the untrained eye, DNA looks like a string of letters.  A gene is a group letters, or a sequence of DNA, that codes for a functioning protein.  Therefore, a gene is the map for the generation of a protein.  In biology, genes and proteins often share the same name and can be interchanged in conversation.  Genes that are passed down from your father and mother are hereditary.  Other genes, referred to as somatic, cannot be passed on through generations.  Therefore, if a gene is mutated in a somatic cell and causes cancer, this mutation will not be passed on to your offspring.  When the scientific literature refers to cancer as a genetic disease, we are not referring to the hereditary propensity of the disease but instead to the idea that mutations in genes, the genetic make-up of each person, can lead to cancer.