What makes cancer cells malignant

And because they divide quicker than usual, there's a higher chance that they will pick up more mistakes in their genes.

This can make them even more immature so that they divide and grow even more quickly. Normal cells can repair themselves if their genes become damaged. This is known as DNA repair. Cells self destruct if the damage is too bad. Scientists call this process apoptosis. In cancer cells, the molecules that decide whether a cell should repair itself are faulty. For example, a protein called p53 usually checks if the cell can repair its genes, or if the cell should die.

But many cancers have a faulty version of p53, so they don't repair themselves properly. Cancer cells can ignore the signals that tell them to self destruct.

So they don't undergo apoptosis when they should. This is called a recurrence. Even if one cancer cell is left behind, it can grow and divide to become a new tumour. A new tumour can start to grow in the same area of the body where the cancer first started, or the cancer may have spread through the blood or lymphatic system to another part of the body, where it grows into a new tumour. This is why doctors sometimes use another treatment right after the first treatment, such as giving chemotherapy after surgery.

This is called adjuvant therapy. The goal of adjuvant therapy is to help prevent the cancer from coming back in case some cancer cells are left behind in the body. In some cases, treatment may stop working become resistant so cancer cells are no longer being destroyed. So cancer that was shrinking or had disappeared may start to grow again and get bigger. This can happen when the genes inside cancer cells mutate. Some gene mutations make cancer cells resistant to chemotherapy and other drug treatments.

If you become resistant to a treatment, your doctor may suggest that you try another one. Many cancers can be cured with treatment. But cancer that is thought to be cured can still come back even years later. This is why some doctors prefer to say that the cancer is in remission.

Remission means there are fewer signs and symptoms of a disease such as cancer or that they have completely gone away. Consequently, the path to cancer involves multiple steps. In fact, many scientists view the progression of cancer as a microevolutionary process.

Figure 1: Microevolution of a cancer cell A series of mutations in a cell causes it to proliferate more than its immediate neighbors.

As the cluster of dividing cells grows over time, further mutations turn atypical hyperplasia into a cancer carcinoma. The spreading of cancer cells to other tissues and organs metastasis occurs when the adhesion of these cancerous cells breaks down, and they are able to travel easily to new locations. The population at the far left side has normal cells; these are shown arranged in a single layer to form a closed, hollow, ring. In the second population, hyperplasia, a group of cells on the left side of the ring begins to divide and increase in number, forming a second and third layer of cells within the ring.

In atypical hyperplasia, the three layers of cells on the left side of the ring have expanded to form a small mass of purple and blue, rapidly proliferating cells. The cells are no longer organized in rows, and some are even piled up on top of one another. In carcinoma in situ , the small mass of cells has expanded further to form a dense population of blue and purple, mutant cancer cells that occupies most of the space within the ring of normal healthy cells.

In the final cell population, microinvasive, a rupture in the left side of the ring of healthy cells has appeared, and several purple, mutant cancer cells are shown spilling out from the dense mass of cancer cells inside. The diagram shows five different groups of cells, which are labeled: normal, hyperplasia, atypical hyperplasia, carcinoma in situ , and microinvasive.

Figure 2 colon is shown in five stages. Normal colon cells are shown at the top of the diagram as a line of six, cuboidal, beige-colored cells, each with a tan, circular nucleus. After the cells accumulate two APC mutations, they develop into an adenomatous polyp.

The adenomatous polyp is shown as an upside-down U-shaped loop of nine yellow, cuboidal cells each with a darker yellow circular nucleus; the yellow cells protrude from the center of the six original healthy beige cells. After acquiring one RAS mutation, the adenomatous polyp develops into a dysplastic polyp. The dysplastic polyp looks like a dense clump of irregularly-shaped, yellow cells of different sizes that fill the upside-down U-shaped cavity.

After acquiring two TP53 mutations, the dysplastic polyp develops into colon carcinoma, in which the clump of yellow cells has changed into a larger mass of orange-colored, irregularly shaped cells of different sizes. After the colon carcinoma acquires chromosomal aberrations, it develops into a metastatic carcinoma. The orange-colored cells have changed to form an aggregation of red, irregularly shaped cells of different sizes with darker red, circular nuclei.

A rupture has formed at the base of the clump, and four of the irregularly shaped red cells appear to be dislodged and falling away from the larger cell aggregation as the cancer spreads. Later, a second mutation might provide the cancer cell with yet another reproductive advantage, which in turn intensifies its competitive advantage even more.

And, if key checkpoints are missed or repair genes are damaged, then the rate of damage accumulation increases still further. Cancer is a disease that occurs when cells become abnormal and grow out of control. Normal cells grow—and then die—when they are given signals to do so, while cancer cells ignore these signals and continue to multiply. The cancer cells may form a tumor at the original site and then spread and form new tumors in other places.

Cancer cells can start to form when our genes, made up of DNA, experience certain changes, or mutations, that cause the cells to behave abnormally. These changes may be due to external factors, such as tobacco smoke and ultraviolet rays. The mutations may also be inherited or completely random. In the human body, there are about major types of cells. These make up the trillions of cells that allow our bodies to function. Limiting processed foods and red meats can help ward off cancer risk.

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