Understanding Cancer's POV - The Tumor Microenvironment
Shoutout @Taili for article idea! This is very cool and very applicable and uses a lot of interesting concepts!!
"Know thy enemy and know yourself; in a hundred battles, you will never be defeated."
- Sun Tzu
In order to understand cancer, we need to understand the perspective of cancer cells within the body. For this, we can study the tumor microenvironment (TME) which describes the environment around the tumor and the local factors influencing its growth.
The TME can be very stiff, or fibrotic, making it hard for chemotherapeutic drugs to penetrate into the area near the tumor and exert their effects. In other kinds of cancers, the TME can be very vascular, facilitating drug transport. Thus, we must determine whether the TME for the specific kind of cancer is vascular or not, and dose drugs accordingly.
Most (80-90%) cancers are carcinomas, which are nonvascular cancers that arise from epithelial tissue. These tend to be fibrotic, and their only method of obtaining nutrients and other necessary compounds is through angiogenesis, which is the promotion of local capillary growth through chemical factors.
Sarcomas are more rare, and are cancers of connective tissue rather than epithelial. These tend to be more vascular, and thus easier to treat due to lower fibrotic character of the TME. Also, due to being fundamentally vascular, angiogenesis is not as important in tumor development (although it still plays a role).
Here's a (kinda strange but still helpful) chart comparing sarcomas and carcinomas:
There are other kinds of cancers as well, with other TME characteristics. I'm not going to go fully in detail here, but I've linked resources below to learn more about other kinds of cancer, including CNS cancers.
A really cool consequence of variable TME vascular supply is that hypoxia (low oxygen which results from low blood supply to the tumor) increases the rate of genetic mutation, which accelerates the progression of the cancer. In addition, as the tumor grows, the surface area exposed to the vasculature (relative to volume exposed) decreases, and there is even more hypoxia as the inner core of the tumor is less exposed to oxygen, which in turn grows the tumor more (due to inhibiting gene repair mechanisms). This is a positive feedback loop.
So um, there's like a million other things I could've gone into. Let me know in the comments / my DMs if y'all want a part 2 of this.
Meanwhile, here are some resources to learn more about TME. It's really very cool.
WIKIPEDIA BABY: https://en.wikipedia.org/wiki/Tumor_microenvironment.
Another nice overview: https://www.mdanderson.org/cancerwise/what-is-the-tumor-microenvironment-3-things-to-know.h00-159460056.html.
More on the differences between carcinomas and sarcomas: https://www.healthline.com/health/carcinoma-vs-sarcoma.
More on cancer types outside of carcinomas/sarcomas: https://www.cancerresearchuk.org/what-is-cancer/how-cancer-starts/types-of-cancer.
