Everyone knows someone who has been affected by Cancer. And so the second half of today’s lecture dealt with one of the most common types; Breast Cancer.
We started off by discussing the basic structures associated with Breast tissue. Below is a picture of the cross section of breast tissue:
1) Rib 2) muscle tissue 3) lobule 4) Nipple 6) Duct 7) Adipose Tissue
Although there are many types of breast cancer these are the four basic and common types.
- Ductal Carcinoma In situ
- Lobular Carcinoma in Situ
- Invasive Ductal Carcinoma
- Invasive Lobular Carcinoma
1-Ductus Carcinoma In Situ:
This is a disease of the ducts and is still considered a cancer even though it does not invade the basal membrane. ( In situ means still within the duct.)
There are 2 grades of DCIS-Low grade and High grade.
a) Solid form-hyper proliferation of epithelial cells
b) Papillary form-you will see fingerlike projections in the lumen
c) Cribriform-large pieces of hole sections resembling swiss cheese
2) Lobular Carcinoma In Situ-Again, this is not an invasion of the basement membrane however this one is not classified as cancer. The important information about lobular carcinoma in situ is that has high risk to progress into cancer.
3) Invasive Ductal Carcinoma-This is the state at which the actual invasion of the basal membrane begins.
4) Invasive Lobular Carcinoma-Here you can see the indian file migration of cells outside the basement membrane
There are many risk factors that correlate and can trigger mutations. Gender is the #1 risk factor due to an increase in female breast tissue as well as exposure to estrogen.
Exam Question: Case study-Perform Risk Analysis
- Increasing Age-more exposure to estrogen
- Family History and Personal History
- Having one first degree relative increases your risk, and having 2 first degree relatives increases your risk 5 fold. Also already having breast cancer increases the chances by 3-4x.
- Race/ethnicity-Asian, Hispanic and Native American woman have a low risk of developing and dying from breast cancer. White women are most at risk of developing breast cancer although African American woman are more likely to die of breast cancer.
- Tissue Architecture-Woman with larger more dense breasts have an increased risk due to more ductal and lobular tissue.
- # of Menstrual cycles- <12 years old or >55 increases risk
- Radiation to the chest-slight increase in risk due to radiation exposure
- Childbirth-This reduces the risk of breast cancer because you do not menstrate during this time period and therefore are exposed to less estrogen. However having a child after age 30 has shown to have a correlation with increased risk.
- Breast Feeding-slightly decreases risk especially for woman who breast feed for up to 2 years.
- Oral Contraceptives-slight increase in risk associated with oral contraceptives although if they have not been taken for >10 years the risk goes back to normal levels.
- Hormone Replacement Therapies-2 types-PHT and ERT. PHT is prescribed to those women who still have a uterus. PHT is used because it contains estrogen and progesterone to offset possible development of uterine cancer. ERT is prescribed for those who have had a hysterectomy and no longer need progesterone. It has been shown that using PHT does increase the risk of developing and dying from cancer. ERT does not show and increased risk unless used for more than 10 years.
- Alcohol Consumption-if used in excess may cause an increase in probabililty http://www.webmd.com/breast-cancer/guide/20061101/alcohol-breast-cancer-risk
- Obesity-obesity is especially correlated with women (or men) that gain weight at a later age. Adipose tissue produces estrogen and increases risk.
- Exercise/Lifestyle-The more active the less adipose tissue
- Diet-diets high in fat are not clearly linked to breast cancer however again more adipose tissue correlates with an increase in estrogen.
- Anti-Perspirant-very weak link between using deodorant and increasing your chances of developing breast cancer.
- Bras-Weak link between wearing bras and increasing your possibility.
- Tobacco Smoke-there has not been conclusive evidence in this debate however smoking does correlate with many other cancer types.
- Breast Implants-the only evidence in this situation is the fact that breast implants make it harder to see developing tissue in mammograms
- Night Shift work-increased risk due to lower levels of melanin
- Estrogen Mimics-theses are compounds found in the environment (BPA) such as my large pink plastic water bottle. These compounds mimic estrogen and therefore may increase risk.
After talking about the risk factors we also talked about some of the beneficial effects of estrogen. Many of the drugs manufactured today mimic the chemical structure of estrogen and therefore can bind with the estrogen receptor. One of the most common drugs is called Tamoxifen. This drug acts as an antagonist to estrogen by binding to the estrogen receptor and not allowing the estrogen receptor to activate gene expression. So therefore you are switching off the effects of estrogen.
This video talked about the correlation of exercise (yoga) with a new drug evista and talked about the side effects being less invasive than even Tamoxifen.
Only 5-10% of breast cancers are traced back to a genetic link. However, when this occurs there tends to be a mutagen to the BRCA1 and BRCA2 genes. These genes typically produce proteins that keep cells from abnormal growth however when they are genetical predisposed to contain a mutation, the chances of developing breast cancer increases significantly. We talked about double stranded breaks in DNA and how BRCA usually binds to these breaks to facilitate the repair. However, if BRCA has been mutated than non-homologous end joining occurs. This process increases rates of errors and therefore mutations
Mutations to Genes ATM, P10 CHEK2 CDH1 and P53 also increase chances of developing breast cancer. However these mutation are much more rare.
After discussing the risk factors in short detail we broke into groups of 4 and began our Risk analysis on 4 different Case studies. Many of these factors above were used in our analysis.
Breast Cancer Walks in Denver 2010 Summer and Fall:
- Sunday October 3rd at the Pepsi Center-Komen Denver Race for the Cure
- Avon Walk Rocky Mountains June 26th-27th