Dear Mesut Tez

how are you? hope you are fine

Of course, cancer no longer considered as a single disease. Now after the discovery of large number of cancers. In the following we have several definitions of cancer, according to:

American Cancer Society

"Cancer is the name for a group of more than 100 diseases in which cells begin to grow out of control"

https://www.cancer.org/cancer/cancer-basics/what-is-cancer.html

WHO

"Cancer is a generic term for a large group of diseases characterized by the growth of abnormal cells beyond their usual boundaries that can then invade adjoining parts of the body and/or spread to other organs "

http://www.who.int/cancer/en/

NCI

"Cancer is the name given to a collection of related diseases"

https://www.cancer.gov/about-cancer/understanding/what-is-cancer

although they have similar behavior "uncontrolled growth" but they are different based on

site of cancer origin, grading, staging, etc

if cancers are a single disease, we will not see these large number of anticancer drugs in the market

in other words, there is no single drug can be used to treat all types of cancer

Good Luck

Definitely and according to available knowledge, cancer is not a single disease but a group of diseases. In epidemiology, diseases are classified in broad sense on the basis of aetiology or manifestation. This is true for cancer. Various cancers might not have the same manifestations or the same aetiological factors.

Dear Mesut Tez

how are you? hope you are fine

Of course, cancer no longer considered as a single disease. Now after the discovery of large number of cancers. In the following we have several definitions of cancer, according to:

American Cancer Society

"Cancer is the name for a group of more than 100 diseases in which cells begin to grow out of control"

https://www.cancer.org/cancer/cancer-basics/what-is-cancer.html

WHO

"Cancer is a generic term for a large group of diseases characterized by the growth of abnormal cells beyond their usual boundaries that can then invade adjoining parts of the body and/or spread to other organs "

http://www.who.int/cancer/en/

NCI

"Cancer is the name given to a collection of related diseases"

https://www.cancer.gov/about-cancer/understanding/what-is-cancer

although they have similar behavior "uncontrolled growth" but they are different based on

site of cancer origin, grading, staging, etc

if cancers are a single disease, we will not see these large number of anticancer drugs in the market

in other words, there is no single drug can be used to treat all types of cancer

Good Luck

Following the line of thought of the above answers we may even say that there are as many cancers as patients having cancer. There are many similarities between different cancers and this similarities were wonderfully described by Hanahan and Weinberg in their Hallmarks... Those are the common traits of different diseases called generically cancer.

So, can we say

" Care more particularly for the individual patient than for the especial features of the disease." — William Osler

or maybe cancer it is one disease with thousands of bifurcation points (?)

and the first bifurcation point is at the cancer transformation point

Dear Andrzej

May be named as "Big bang"

Dear Mesut

yes, exactly

Medical care by its nature is individualized care. Doctors deal with each patient as a separate case from all others. However accumulated experience must be used to formulate general and common principles and protocols to deal with a line of disease patterns. This is true for cancer.

"Wisdom is to walk in two opposite directions at the same time" (from https://www.researchgate.net/publication/314155374_Cellular_acidification_as_a_new_approach_to_cancer_treatment_and_to_the_understanding_and_therapeutics_of_neurodegenerative_diseases?_iepl%5BviewId%5D=mW8G68sTiXBMDLI6y3sALkfk&_iepl%5Bcontexts%5D%5B0%5D=projectUpdatesLog&_iepl%5BtargetEntityId%5D=PB%3A314155374&_iepl%5BinteractionType%5D=publicationTitle)

So, from https://www.researchgate.net/publication/314512057_The_new_pH-centric_anticancer_paradigm_in_Oncology_and_Medicine, we have:

a) "Looked at from the genetic point-of-view cancer represents adaunting and, frankly, confusing multiplicity of diseases (more than 100) that require an equally large variety of therapeutic strategiesand substances designed to treat each particular tumor"

and

b) "This new and integral approach to the different stages and the many faces and manifestations of cancer opens new avenues to both increasing our understanding of cancer as a single disease process and to improve the treatment of malignant disease"

I prefer point b), i.e. cancer is a single disease

Dear Andrzej

I hope so

As Dr. Tomas said and the following link may help

have been trying to understand to cancer for the last thirty years but following link does not help