Cancer - Types of Cancer, Causes, Symptoms and Treatments

The word cancer comes from the Greek karkínos, meaning crab (because the veins of tumors resemble the legs of a crab) and is the name given to a group of more than 100 non-contagious diseases characterized by uncontrolled cell proliferation. Although there are varied types of cancer, all starts from the abnormal and uncontrolled growth of cells.

The process of carcinogenesis, that is, the formation of cancer, starts from cells of some tissue or organ of the body that begin to grow wildly, lose the ability to differentiate, and thus are no longer specialized in a given function, resulting in abnormal cells, which can multiply and invade other organs. In general, this process occurs slowly, and may take years until the tumor appears.

Cells are the structural and functional units of living organisms. Under normal conditions, most cells grow, multiply, and die in an orderly fashion. The process of cell division, which gives rise to new cells from a "mother" cell, is extremely regulated, so that life-sustaining, growth, and aging processes are performed. In this process are involved structures called genes, which are composed of DNA (deoxyribonucleic acid), where the genetic information of the human being are present. The genes responsible for cell division are called proto-oncogenes, and when for some reason a genetic mutation, that is, a genetic fault occurs, these genes can turn into an oncogene. In turn, an oncogene is a gene related to the onset of tumors, both malignant and benign.

The differentiation between malignant and benign tumors is basically related to the mechanism of metastasis, a process in which the tumor has the ability to spread and invade other organs. Benign tumors do not have the capacity to cause metastases, malignant ones are aggressive and have the capacity to infiltrate other organs.

The most common types of cancer are: skin cancer, lung cancer, breast cancer, prostate cancer, cervical cancer, cancer of the mouth, colorectal cancer, cancer of the stomach, among others. Also, there are categories that group the types of cancer according to the histological type, which is the embryonic origin of the tissues from which the tumor is derived, they are:

Carcinoma - develop in epithelial cells that cover our skin and most organs. Among the carcinomas there are subtypes: adenocarcinoma, basal cell carcinoma, epidermoid carcinoma and carcinoma in situ.
Sarcoma - are relatively rare, arise from tissues such as muscles, cartilage, blood vessels and bones.
Leukemia - originated in the bone marrow, where the blood cells are produced. They are divided into myeloid and lymphoid, according to the cell involved.
Lymphoma - reach organs and structures of the lymphatic system, fundamental in maintaining the defense of our body against infections. They are classified into two categories: Hodgkin's lymphomas and non-Hodgkin's lymphomas.

Although cancer represents many heterogeneous diseases, and there is a genetic factor in the development of the disease, several types may have in common the same associated risk factors, such as tobacco use, alcohol, inadequate diet and virus infection, such as Papilloma human virus (HPV).

The diagnosis of cancer is made from the patient's medical history, a detailed physical examination, and if possible examination to visualize the affected area. The treatment with chemotherapy, radiotherapy and in some cases surgery, are the most used resources in the fight against cancer. Early diagnosis enables treatment and even cure. The science that studies cancer is called Oncology.