Diagnosis of Cancer – Neoplasia

00:01 Let's do diagnosis. IHC is huge. Immunohistochemistry. And it's only getting bigger.

00:08 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.

00:23 If it's a desmin. Let me give you a muscle cancer. Ready for this one? You have a young girl.

00:30 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.

00:41 That is rhabdomyosarcoma of a little girl. Welcome to what's known as sarcoma botryoides.

00:48 That's a rhabdomyosarcoma and that's your EMS, embryonal rhabdomyosarcoma.

00:54 What kind of marker are you going to find there? Desmin. Are we clear as to when you would use your Desmin.

01:01 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.

01:15 That is your osteosarcoma and that would be your Vimentin. And that would be a sarcoma.

01:24 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.

01:44 They are not going to give you a patient that has frequency and inability to void. That's BPH.

01:50 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.

02:03 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.

02:15 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.

02:33 That's what prostate cancer would feel like. You would expect for there to be an increase in PSA.

02:38 Actin is just to make sure we are complete smooth and skeletal muscle but you are paying attention to Desmin more so.

02:44 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.

02:56 Estrogen. Where would you be if there is estrogen receptors? Big time. Pharmacology as well.

03:02 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.

03:36 Right? Monoclonal antibody. Let's do S100. Many have learned that S100 is melanoma. Okay, yes, true.

03:45 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.

03:58 From henceforth though, take the S100 you focus upon the 'S'.'S' will be for skin.

04:04 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.

04:23 We will hit each and every one of those separately. Point is, melanoma with S100 is non-specific.

04:30 You should know a molecular called BRAF. We will talk about that further.

04:36 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.

04:45 It has the RAF in it. Look for it. Then you have TG, Thyroglobulin.

04:51 With thyroglobulin, this is something that, now for this I need your help.

04:56 Meaning to say, thyroid hormone synthesis from physiology is what you are thinking.

05:00 The iodine goes into the follicular epithelial cell with the help of your sodium-iodide symport.

05:06 Next, you get your iodine in. In the meantime, in the follicular epithelial cell in the endoplasmic reticulum, what protein is being synthesized? Thyroglobulin.

05:19 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.