"Cancer" is a word used to describe a number of different diseases. Many different types of cancer have many different traits: the speed at which the tumor develops, the therapy that is used to treat it, the outcome, the way that it spreads... One of the few common things for all different types of cancers is how they start.
Our body is a complex system of different types of cells, which form tissues, which form organs etc. Every cell has it's duty and a life span. Some cells live only a few days, before they die and are replaced with new ones, like the cells in our intestines. The others are alive for as long as we are (the neurons, the cells in our brain). Every now and then, a mistake in a random gene happens, and the cell starts acting weird. It doesn't do what it's supposed to do, for instance, it doesn't produce the type of protein that it usually produces. The evolution has developed mechanisms to eliminate these cells from the organisms.
First, there are intra-cellular molecular mechanisms of repairing the damaged DNA. If that fails, there is a "security switch" in every cell that triggers apoptosis. Apoptosis is programed cell death, basically suicide. But, from time to time, cells are able to override this security switch. That's when our white blood cells move into action.
There are certain types of white blood cells that move across our organism and check every cell for "malfunction". If they find that type of cell, they kill it. Since there are many cells in our organism, it doesn't surprise that this situation happens at least once a day. But, sometimes, a corrupt cell is able to hide from the white blood cells searching for it. That's when the cell goes rogue. It starts reproducing uncontrollably and sometimes even orders the organism to form new blood vessels to keep it fed and oxygenated. That's, in short, how tumors develop.
There are many different ways in which a mutation can develop: UV light, exposure to toxins, heavy metals, radiation... One of the factors that can cause tumors are viruses. What viruses do is they enter the cell and incorporate the host's DNA, thus overtaking the cell and making it replicate the virus DNA and produce proteins the virus needs. Hepatitis virus B (HBV) does that too.
What does HBV do?
When HBV invades the cell, it appears inside the cell in two forms: the circular form, and the integrated form. The circular form codes four proteins needed for the virus to replicate (all of which have been found in liver cancer cells), while the integrated form enters the host DNA. One of the proteins, that the circular DNA codes, shuts down the molecular defense mechanisms against cancer, including programed cell suicide, while the integrated DNA promotes growth and replication of the infected cell, among other things.
About hepatitis B
Hepatitis B is caused by hepatovirus B. It is transmitted by blood and other bodily fluids. One of the ways it can be transmitted is from an infected mother to child, at childbirth. The illness can take one of two forms: acute and chronic. The age at which the person gets infected largely influences the form the infection will take. The younger the person-the greater the risk for a chronic infection. The acute form lasts for a few weeks, or for a few months, and the infection is cleared from the organism spontaneously. Once the infection is over, the organism is immune to HBV, which means that you can't get hepatitis B again.
Chronic hepatitis B infection means that the virus hasn't cleared from the organism in six months. Over 90 percent of infants infected at birth develop chronic hepatitis, unless they get vaccinated within the first 24 hours. Chronic hepatitis can be managed, but, if left untreated, it can cause serious problems. Up to 25 percent of people with chronic hepatitis B develop liver problems, such as liver failure, cirrhosis and liver cancer.
What can we do about it?
The first, and most important step is prevention. There is a vaccine against hepatitis B, and the WHO suggests that it should be administered to infants within the first 24 hours after birth. If, for some reason, this vaccination is skipped, adults can also get a vaccine. There are parts of the population that are at more risk from the hepatitis B infection than the others. These groups include:
- IV drug users
- People who live with people infected with hepatitis B
- People who have diabetes
- People who are not in a monogamous sexual relationship
- Healthcare professionals
There are about 2.2 million people living with hepatitis B in the US. This virus is up to 100 times more infectious than HIV, and it is very important to use prevention. Other means of prevention, save for vaccines, include: practicing safe sex, using protection when handling infectious materials, always using new syringes, and covering open cuts and wounds with waterproof dressings as soon as possible.
There is therapy for chronic hepatitis B infections. This therapy can't eliminate the virus from the organism, but it can delay or eliminate the complications caused by this infection.
Hepatitis B is a very infectious disease transmitted via infected blood and other bodily fluids. Risk factors include using unsafe needles for whatever reason, unsafe sex and getting a tattoo or a piercing in an unsanitary institution, among others. Although there is a therapy for chronic hepatitis B infection, it can never be fully cured, so vaccination is strongly advised. This disease can cause cirrhosis, liver failure and liver cancer (especially if co-infection with hepatitis D is present), but it is easily preventable using vaccination.