Q.1. What is the reason of cancer? where does it starts?

Ans. I think these two questions are quiet similar. According to my understanding it is a two way process from genetic changes to physical abnormality and from environmental changes to genetic changes. In the process of evolution our genetic material changes for better survival often it is a curse which is known as cancer. Secondly our environment influences our genetic material to change in a specific direction which could be good or bad. As for a example carcinogen present in cigarette. Also cigarette is basically our choice not so much environmental influence.

All these are very basic idea which we all know but we do not able to fathom what is the single reason of cancer and where does it starts. To my understanding development of cancer is a intricate crosstalk between multiple environmental factor including pressures of nature, anthropogenic activities and individual's cellular changes (germ line and somatic ) .

Though I am not an expert, hope it is helpful. Also I hope that in this community so many experts are there they will able to provide you much more specific answer.

Q.2. Who is the master?

First is "mother nature" second is "human being".

Cancer effectively happens when a cell multiplies uncontrollably and develops an abilty to spread and survive outside its normal location (metastasise).

The problem is - there is no master - it is cellular anarchy. The cause ultimately involves damage to the DNA - at a coding or non coding part - or even at a chromosomal level. The damage'breaks' control of growth and endows the cell with abilities to 'break free'. The cause of the damage in any specific case is rarely known (unless it is hereditary ex BRCA1 mutations in breasr cancer) however several factors can cause DNA damage: UV, X rays, chemical mutagens ex in smoking..,

Specifically this involves moditying oncogenes, tumour suppressor genes, cell adhesion molecules, turning on angiogenesis, telomere elongation and others which I have not thought of. These changes are thought to accumulate in a stepwise/parallel manner in a population of cells until one/more 'break free' (think of it as survival of the fittest).

Remember that, just like emergence of bacterial antibiotic resistance, the cancer 'evolves' 'finding' different ways to evade control (a cancer cell finds it easier to accumulate new DNA damage some of which endows new properties).

Unfortuunately the specific changes differ from tissue to tissue and in a lot of cases the precise sequence/s is not known. Eventually the patient dies from destruction of normal tissue by widespread cancerous growths coupled with other tumour effects - anorexia, loss of weight, immunosuppression etc.

Newer tools like whole cancer genome sequencing and massive computer power to analyse the massive data generated will lead us closer to understanding and hopefully identifying crucial 'control' points or possibly weaknesses in the cancer.

There are plenty of published works dealing with the different causes of different cancer types, and different key players are involved, so not just one master.

See hallmarks of cancer from Hanahan&Weinberg. Also regarding mother nature: check out the beautiful video of Judith Campisi http://www.sens.org/videos/senescent-cells-cancer-and-aging-dr-judith-campisi

There are certain enzymes produced by the body which metabolize protein. These enzymes also metabolize abnormal early-stage cancer cells, however, as long as there is food to be digested they will prioritize these proteins and neglect the cancer cells. Constant and excessive protein consumption allows the cancer cells to multiply to the point they overwhelm the natural immune system and create tumors.

When cell starts multiply in an uncontrolled manner then it is results in tumor formation. When tumor cells starts migrate from their location, then it is called as cancer.

So, the process which promotes cell migration in tumor cells might be the cause for cancer. This event to be studied in detail to get rid off cancer from the universe.

I refer you to a book, ONE ANSWER TO CANCER by Dr. William Donald Kelley DDS MS, originally from Grapevine, Texas. Just google the title and it will pop up online. It is a phenomenally interesting insight into the etiology of cancer. You'll truly enjoy it, I promise.

I am not a cancer researcher. I only know what I see and what I read in publications, which I admit is limited. I simply want to contribute to the conversation and not attempt to be any kind of authority. I am old-school and ignorant of the latest DNA research on laboratory animals. Dr. Anu asked a question, and I just expressed my own anecdotal opinion based on what I have observed in my own clinical practice.