Thread by @SfPRocur

Yoga? 🧘🏼‍♀️ ✅
Breakfast? 🍳 ✅
First cup of coffee? ☕️ ✅

Let’s get started!

Today I’ll be tweeting Breast Cancer 101: what it is and how it’s treated. Tomorrow I’ll focus on my research on endocrine resistant breast cancer.

If you have questions, please ask!

Let’s start with the basics.

Cells are the building blocks of an organism and work together to make tissues and organs. Together, organs help your body function. Each level along this continuum is different for each organ - a muscle cell is different from a neuron (brain cell).

Cells are made of molecules including DNA, RNA, and protein.

The central dogma describes how DNA makes RNA that makes proteins.

Largely, proteins are thought to “do” things in the cell - they are enzymes that catalyze reactions, receptors that signal, provide structure, etc.

The central dogma happens in nearly all of your cells all day every day.

These proteins help your cells perform their normal functions: secreting acid in your stomach, creating a protective barrier from the world in your skin, and absorbing oxygen in your lungs.

The world is a scary place 😋 - new cells need to be made and old cells need to be safely removed.

You may have learned about mitosis (PMAT!) and cytokinesis which are the processes of DNA replication and cell division. This process is supposed to happen under tight control.

Put most simply, in cancer DNA is damaged which often leads to the wrong kinds of proteins being made.

Proteins that tell the cells to stop growing are no longer made and those that help cells grow are made at a higher rate.

Which cells divide the most?

Cells exposed to the external environment need to divide more (because they are exposed to more damage) - think your skin, GI tract.

And the tissues whose cells divide more have a higher likelihood of developing cancer. science.sciencemag.org/content/347/62…

Another thing to note is that cancer is a disease of age as demonstrated by this graph from @theNCI - the older you are, the more cell divisions, the higher likelihood of developing cancer. (Also important to consider is this isn’t absolute!)

What about breast cancer? I was trained to think about normal tissue to understand how cancer develops so let’s start there.

The mammary gland is the tissue in the breast that ultimately produces milk for the offspring. It grows in response to hormones throughout a woman’s life.

The mammary gland is made of ducts that originate at the nipple and develop toward the chest wall. The ducts end in lobules that if signaled (by hormones in pregnancy) produce milk.

The gland - or parenchyma - is surrounded by connective tissue including fat.

At the microscopic level, the epithelial cells make up the gland. These are the cells that more often than not become breast cancer.

(This amazing figure can be found in this article from the Bissell lab: dev.biologists.org/content/142/6/…)