Let's do diagnosis. IHC is huge. Immunohistochemistry.
And it's only getting bigger.
Let me give you the basics at least at this point.
Cytokeratin, you tell me please? Sarcoma or carcinoma?
Good. With cytokeratin you are thinking about your
carcinoma. The origin would be epithelial cells.
If it's a desmin. Let me give you a muscle cancer.
Ready for this one? You have a young girl.
Maybe 2 years of age. And you take a look at
the genital region and you find,
literally on gross examination grape-like
clusters that is coming out of her vagina.
That is rhabdomyosarcoma of a little girl. Welcome
to what's known as sarcoma botryoides.
That's a rhabdomyosarcoma and that's your
EMS, embryonal rhabdomyosarcoma.
What kind of marker are you going to find there? Desmin.
Are we clear as to when you would use your Desmin.
Vimentin will be mesenchymal. In the previous discussion
would it be a carcinoma or sarcoma in which the marker
here would be Vimentin? I showed you a picture here of
osteosarcoma and I showed you a picture of that metaphysis.
That is your osteosarcoma and that would be
your Vimentin. And that would be a sarcoma.
If it's PSA, now on your boards you still will be
using prostate specific antigen to note or
monitor a prostate cancer. What kind of
description are they going to give you?
They are not going to give you a patient who is a male
obviously, that is going to have difficulty with urination.
They are not going to give you a patient that has
frequency and inability to void. That's BPH.
So what you want to do before we go on to pathology
is make sure that you are clearly understanding
BPH, benign prostatic hyperplasia which is not at
all cancer, versus prostate cancer.
That's why I told you would'nt have the symptoms of BPH.
Why? Because prostate cancer as far as you are concerned,
it most likely will not be peri-urethral.
It's not in the central zone.
Well, you do a digital rectal examination. You place a finger
on the prostate and are you able to feel prostate, cancer?
As far as you are concerned, yes. What does it feel like?
Feel your chin. See my ugly chin. It's gritty, hard.
That's what prostate cancer would feel like. You would
expect for there to be an increase in PSA.
Actin is just to make sure we are complete smooth and skeletal
muscle but you are paying attention to Desmin more so.
CD will tell you what kind of lymphoma or leukaemia.
Remember if it was the lower types of CD's
like CD5, CD1 and such that's T-cell. If it's B-cell
then you are thinking about CD19, CD20, CD21.
Estrogen. Where would you be if there is estrogen
receptors? Big time. Pharmacology as well.
If your patient is ER+, estrogen receptor positive, would you please
tell me what kind of drug class that you might be thinking about using?
Tamoxifen, raloxifen. Partial agonists, right?
Estrogen. If there is too much estrogen
especially estrogen receptors. You have heard of
HER2/neu? What's HER stands for?
Human epidermal growth factor receptor. Amazing.
What do you know about HER2/neu?
It's the most aggresive type of breast cancer. Luckily,
we have treatment. What's it called? Trastuzumab.
Right? Monoclonal antibody. Let's do S100. Many have
learned that S100 is melanoma. Okay, yes, true.
But that's non-specific. Why? Big time here. Let me
walk you through this. New information, that you are
very much responsible for on your boards. S100,
sure absolutely could be part of melanoma.
From henceforth though, take the S100 you focus
upon the 'S'.'S' will be for skin.
Therefore, there are many types of skin
cancers apart from melanoma, right?
You can have squamous cell cancer, basal cell carcinoma
and other types of T-cell lymphoma such as your
S?zary syndrome or adult T-cell leukaemia/lymphoma. I just
gave you a bunch of differentials. Do not feel overwhelmed.
We will hit each and every one of those separately.
Point is, melanoma with S100 is non-specific.
You should know a molecular called BRAF.
We will talk about that further.
And why BRAF becomes important to you is because there is a drug
that you can actually use to fight off the melanoma called vemurafinib.
It has the RAF in it. Look for it.
Then you have TG, Thyroglobulin.
With thyroglobulin, this is something that,
now for this I need your help.
Meaning to say, thyroid hormone synthesis
from physiology is what you are thinking.
The iodine goes into the follicular epithelial cell
with the help of your sodium-iodide symport.
Next, you get your iodine in. In the meantime, in the
follicular epithelial cell in the endoplasmic reticulum,
what protein is being synthesized? Thyroglobulin.
So therefore, if you are thinking about thyroid cancer,
the most common being papillary cancer of the thyroid,
you are going to monitor thyroglobulin. In fact,
any time that you have thyroid cancer,
you are going to monitor thyroglobulin.
Clinically, that is absolutely imperative.