Overall, they include drugs that have long been abused, such as marijuana and cocaine, and drugs whose abuse is a more recent development. Some are stimulants, some depressants, and some hallucinogens-while most exhibit multiple pharmacological properties.
Studies of PCBs in humans have found increased rates of melanomas, liver cancer, gall bladder cancer, biliary tract cancer, gastrointestinal tract cancer, and brain cancer, [1] and may be linked to breast cancer. PCBs are known to cause a variety of types of cancer in rats, mice, and other study animals. [2].
This theory states that 15% of cancers are caused by viruses. One example is HPV, which causes cervical cancer i.e. cancer of the cervix in women. The virus is lysogenic and it inserts a destructive gene into the tumor suppressor T53 gene. This allows a mutated oncogene to cause a cell to become cancerous.his theory states that 15% of cancers are caused by viruses. One example is HPV, which causes cervical cancer i.e. cancer of the cervix in women. The virus is lysogenic and it inserts a destructive gene into the tumor suppressor T53 gene. This allows a mutated oncogene to cause a cell to become cancerous.