Though cancer is defined as the abnormal and uncontrollable process of growth of cells yet its true nature is unknown and obscure. Multitudes of factors are responsible for its growth and development.
Oncogenes are related with cancerous and necrotic cells. What is cancer? In simple language cancer is abnormal and uncontrollable growth of cells. Cancer is abnormal proliferation/ replication and multiplication of certain damaged cells. We all know that cell is biological unit of human life it is the foundation stone of human life.life is composed of tiny highly organized cells, unseen by naked human eye. According to biogenesis theory oflife, new cells are produced out of existing cells. Cell growth and cell development is paramount to human life. The first cell out of which life evolved was Coacervate. Coacervate was cell like in which true cell organizational structure was absent. True nucleus was absent in Coacervate. Prokaryotes were the first organism evolved on this earth. The first prokaryotic cell was bacteria and Monera. Out of single celled organism evolved the multicultural organism. With multiplication of cells by mitosis came the tissues and from tissues formed the organs than fully developed organism. Thus cell is primary unit of life out of which whole range of life has evolved. You must have seen how the child grows in size and length with the advancement of time and age? This is possible only with the multiplications of various kinds of cells. The growth process of cells continues unto adulthood or unto teenage. There after it stops growing new cells.
DNA is our hereditary unit. It is our genetic material and capable of self replication. It is mainly found in the nucleus of cell. All our hereditary characters are hidden in DNA. DNA is store house of all our biological instructions. Our biological instructions are encoded in the structure of DNA.DNA stands for deoxyribonucleic acid. One molecule of DNA.consists of pentose sugar (deoxyribose) phosphorous and nitrogen bases.DNA is long chain of helical like structure of nucleotides with nitrogen bases. Nucleotides are complex organic molecules. The structure and shape of nucleotides determines the shape and structure of our tissues and organs. Human body has 23 pairs of chromosomes out of which one pair is sex chromosomes and 22 pairs are of autosomes. The sex chromosomes determines the sex of he new born child. Chromosomes are further units of DNA. Than come the genes which are located on chromosomes in a linear fashion. Genes further determine the structure of our body and enzymes. There are specific geneses for specific body functions. There are different genes to determine height of human body and color of our skin and eyes. Starting from cellwe have come to genes. Gene is that portion of DNA that codes for one enzyme later it modified to one gene one polypeptide hypothesis.
The next step to understand Oncogenes is that DNA is not stable. It is vulnerable to external factors like ultraviolet rays and radiations can cause damage theDNAstructure. This damage leads to mutations. Mutations are sudden and spontaneous changes in the structure of DNA, chromosome or gene. The genius Hugo de vries was the first scientist to float the concept of mutation. There after started the scientific studies of gene mutations. Muller in 1927 demonstrated for the first time that mutations can be induced by x-rays. When DNA is damaged our body tries to repair it naturally but when it can not be repaired than the genes turn into Oncogenes. Now what are Oncogenes? Oncogenes are cancer causing or cancer producing genes in our body. Cancer is negative process of cell reproduction and multiplications. Oncogenes produce a new colony of mass called tumor so the mutated genes or damaged genes are responsible for the new abnormal growths called tumors in our body. Malignancy is altered state of DNAand genes. Due to various factors some known some unknown a normal gene starts functioning like a foreign gene in our body and goes transformation. This transformation is real culprit of Oncogenes. And Oncogenes further give rise to cancerous cells and new growths in our body. In which part of our body this transformation of healthy genes takes place there new growths are formed. If it takes place in breast than carcinoma of breast is formed. If it takes place in blood than blood cancer is produced. The cell containing Oncogenes begin making copies of itself in a rapid manner which in turn continues to multiply and proliferate uncontrollably thus forming malignant tumor. In biological terms it is called replication. Replication is the process of producing of multitude of identical copies from its original copy and this tumor is empowered by its own net work of blood vessels. The new proliferation of cells is not only useless for our body functions but harmless too. It should be born in mind that cancer is still a mystery for science to solve and it is most complicated process in which besides Oncogenes other multitude of factors are also involved. Cancerous growths in human body are not so simple a process as I have tried to make it understand. I have drawn only its outer lines to understand for the curious mind.