Has science helped us to understand and defeat cancer?
In the past few decades, we've learned a great deal about the genetic alterations that play key roles in carcinogenesis (the biological process that leads to cancer). Have these scientific breakthroughs reduced the cancer death rate from cancer? Have they lessened our confusion about this terrible disease?
There are literally hundreds of distinct types of cancer. Pathologists can distinguish all these cancers by their clinical, gross (the morphology of the tumor visible to the unaided eye), anatomic (location of the tumor) and histologic (the morphology of the tumor cell visualized with a microscope) features. In some cases, genetic studies further enhance our ability to distinguish one cancer from another.
Why are there different kinds of tumors? If cancer is a single disease, why is there not one single kind of cancer, representing the end-point of carcinogenesis? Every person is a unique individual, with unique genes. Why do cancers, of a specific type, have the same features when they occur in different individuals? We are told that cancers have genetic instability. If the genes in a cancer are constantly changing, should there not be an infinite number of different cancers? In fact, wouldn't you expect a single cancer to change its type, morphing from one kind of cancer into another kind of cancer, as its genes alter.
When we learn that a specific oncogene (activated cancer-causing gene) is found in a specific type of tumor, what does that tell us about cancer, in general, when other tumors do not contain the same oncogene? Can we be certain that all tumors are caused by oncogenes? What controls, or reverses, the carcinogenic process? Can we draw any conclusions about the general development of cancer, by studying a single type of cancer?
It is all very confusing.
If you want to learn something about cancer, you have a choice of two types of books. There is the basic cell biology book, that tells you about oncogenes and tumor suppressor genes and treats cancer as though it were one disease, with one biological process. Yes, the oncogene for one tumor may be a different gene than the oncogene for another type of tumor, but it is generally assumed that the same principles of cancer development apply to any tumor. There are other books that list all the different types of cancer, supplying the clinical, anatomic and histologic features that distinguish one tumor from another. Both these books fail to organize scientific and pathologic information in a manner that helps us to understand the differences and the unifying principles that apply to biological classes of human tumors.
I wrote Neoplasms: Principles of Development and Diversity, to provide the biological and clinical connections between between different types of cancers. Many of the lessons in Neoplasms come from observations that have not appeared in other books. The book begins by exploring tumor speciation (why we encounter a diversity of cancers). This is followed by employing the principles of tumor speciation to develop a useful and comprehensive tumor classification. Nothing we learn about cancer means anything if it cannot be used to reduce the number of deaths due to cancer. The third and final part of Neoplasms is devoted to cancer eradication.
Since publication of Neoplasms: Principles of Development and Diversity, on Oct 1, 2008, I've been including excerpts of this book in my blog. I'll continue to include short excerpts over the next several weeks. After that, I plan to go back to writing may random thoughts about the organization, annotation, retrieval, and analysis of biomedical information.