You are here

Molecular oncology and cancer

Imagine how immense the universe is, and our planet earth a tiny molecule in the vast space filled with galaxies and stars.

Then imagine our chromosomes, 46 individual one in 23 pairs, each containing billions of codes. These codes are simply four letters: A, T, G, and C.

Then imagine a molecule, a gene, inside a cell, a cell, only visible under a microscope (except an egg of an animal).

DNA (Deoxyribonucleic Acid)

  • A pairs with T and G pairs with C.
  • A combination of three letters in a row codes for an amino acid.
  • We have a total of twenty different amino acids in our body that make up tens of thousands of proteins.
  • These proteins are coded by genes.
  • Each of human cell express twenty to thirty thousand genes.
  • We have total of thirty or more genes in our body. Yet, it is not just the coded genes that are important.

RNA (Ribonucleic Acid)

More than a decade ago, a new class of molecules was discovered, called small interference RNA (siRNA). This discovery revolutionizes a new field of biology that has deepened our understanding of how life operates in fascinating and intriguing ways. These RNAs do not code for proteins.

History

Yet, it has been nearly four hundred years in the making to have come to this vantage point since the first time a human saw a "cell" in the 1660's with a most primitive microscope. By that time, Isaac Newton had already laid out the foundation for gravitational physics and infinitesimal calculus. Biology was way behind physics.

Then let's fast forward, to the 1950's, when Watson and Crick discovered the structure of DNA, the building block of life, revealing the secret of how genetic material is passed from generation to generation, how life goes on and on. (four decades before the discovery of DNA, Einstein had already figured out the Theory of Relativity).

It took another twenty some years for molecular biology to achieve solid footing. Only after several proteins such as restriction enzymes, RNA reverse transcriptase, and others were discovered in the 1970s and 1980s, it became possible to dissect the mystery of genes in great detail.

By the 1990's, cloning genes was a way of life for molecular biologist. In 2000, the whole human genome was decoded. And today's hottest research is about how life renews itself- the function of stem cells.

Stem cells

  • Stem cells are a group of specialized cells that are capable of regenerating cells that are armed to work with specific tasks in organ and systems.
  • Stem cells are controlled by genes in a very strict fashion and live in a special environment in each organ of human body.

Cancer cells

  • Yet, cancer cells are the cells that are out of control.
  • Many of their genes are mutated. Years ago it was thought that each cancer cell perhaps harbored mutations of a dozen or so genes. However, only a few years ago, the National Cancer Genome Atlas project found that a cancer cell actually harbors more than two hundred gene mutations.

Cancer cell mutations

  • Each cancer cell also has its own specific mutations.
  • Cancer cells make new mutations over time.
  • This makes them resistant to treatment and it is why most of metastatic cancer is still difficult to cure.

Targeting gene mutations

Finally, about a decade ago, targeting of a specific gene that is mutated and or out of control in cancer has come to fruition.

  • The first such targeted drug, was a small molecule called imatinib (Gleevec), approved by the FDA in 2000, which opened the door for numerous other similar drugs to follow.
  • Today we have more than a dozen similar drugs for cancer therapy that have been developed.
  • For example: Imatinib inhibits three genes: ABL, c-Kit, and PDGF receptor. They are tyrosine kinases, a class of protein enzymes that are often mutated or out of control in cancer.
    • Other drugs target different genes to treat cancer. Some are even more powerful than imatinib. Many can control cancer for months. Some patients may benefit from a drug for years.

Individualized medicine for cancer therapy

Targeted therapy also brings about individualized medicine for cancer therapy.

  • Because different cancer harbors different gene mutations and different patients have different gene makeup within their cancer, using specific drugs that targets the individual genes that are mutated in each patient's cancer, would be more effective and selective.
  • To understand specific genes and gene mutations in each cancer, many molecular tests have been developed to identify genes and gene mutations that can help predict outcome of treatment.

Future of cancer therapy

Despite the progress so far, curing advanced cancer still remains a challenging task. Much work still needs to be done to bring better treatment to cancer patients. The most promising areas that may bring about breakthroughs in the future of cancer therapy include cancer vaccines and small interference RNAs.

I hope this brief summary of molecular oncology has been useful to you. I wish you the best in you endeavor to understand the impact of molecular oncology on cancer treatment.