Cancer, according to American Cancer Society, includes a group of more than 100 diseases where cells in a part of the body begin to grow out of control.

While normal body cells grow, divide and die in an orderly fashion, cancer cells continue to grow and form new, abnormal cells instead of dying. Cancer cells can also grow into other tissues, something that normal cells cannot do. After a series of random mutations, healthy cells can become cancerous, causing some genes to be over-activated and other genes for regulations shut down. The cells growing out of control would multiply into a tumor.

Recent discoveries have complicated the general understanding of cancer, which has now proven out to be more willful than thought.

While only around 2 percent of the human genome was thought to carry the code for making enzymes and other proteins that are cancer-generating, researchers have newly suggested that there are oncogenes lurking within the other 98 percent, which had been long considered "junk DNA."

"We've been obsessively focusing our attention on 2 percent of the genome," says Dr. Pier Paolo Pandolfi, a professor of medicine and pathology at Harvard Medical School, reported the New York Times. At the annual meeting of the American Association for Cancer Research in Orlando, Fla., Pandolfi described a new "biological dimension" where signals from both regions of the genome participate in the delicate balance between normal cellular behavior and malignancy, said the Times. It turns out that over 90 percent of the protein-encoding cells in human body are microbial, according to cancer researchers.

Additionally, a protein called JAK was newly identified as a helper for the cancer cell to spread out of tumor into other parts of the body - a discovery that offers clues for new drugs to prevent cancers spreading.

Cancer Research UK-funded scientists have claimed that JAK protein can make cancer cell contract like a muscle, allowing them to move between tissues. Then the cancer cells would squeeze into tiny spaces and proliferate into a cancerous tumor and spread into new regions of the body.

Around 90% of cancer-related deaths occur when the cancer spread beyond the initial tumor into other organs of the body, in a process called metastasis.

The finding raises the potential for drugs targeting JAK to stop the spread of tumors during metastasis.

Cancerous cells can move in two ways. In some cancer types the cancer cells use force to 'elbow' their way through the matrix. The force is produced by a process similar to muscle contraction. In other types of tumors, the tumor-associated healthy cells use force to create tunnels down which the tumor cells move.

The same processes are used to generate force in cancer cells and in the tumor associated normal cells, according to the scientists.

"We've shown that the same protein called JAK triggers tumor spread via two different routes - it generates the force needed for cancer cells to move around the body and also for triggers healthy cells in tumors to create furrows in tissues down which cancer cells move," said

Lead author Professor Chris Marshall, a Cancer Research UK-funded scientist from The Institute of Cancer Research.

Protein JAK has already been linked to leukemia, and some drugs in development are targeting the protein.

"Encouragingly drugs that block JAK are already in development to stop the growth of tumors. Our new study suggests that such drugs may also stop the spread of cancer," said Marshall.

"Discovering how cancer cells can funnel grooves though tissues, to squeeze away from primary tumors and spread to new sites, gives scientists fresh understanding of ways to stop cancer spread - literally in its tracks," says Dr Lesley Walker, Cancer Research UK's director of cancer information.