What is Ki67?

[DianneS]

Can someone explain this? I didn't see it on my tumor/path results.

I know there is a member here who lives in the Toronto area and maybe Princess Margaret Hosp. does this test ?? but they don't seem to do it here in B.C.

Diannes

[Joe]

Question: What is the Ki-67 Tumor Marker Test for Breast Cancer?

Ki-67 is a cancer antigen that is found in growing, dividing cells but is absent in the resting phase of cell growth. This characteristic makes Ki-67 a good tumor marker. This test is done on a sample of tumor tissue, to help predict your prognosis.
Answer: About the Ki-67 Tumor Marker

Although the Ki-67 test is not always used for breast cancer, many studies have been done to determine its value as a tumor marker test. The researchers agreed that high levels of Ki-67 indicate an aggressive tumor and predict a poor prognosis. A British study found that breast cancers could vary in regards to hormone-sensitivity, lymph node status (positive or negative), but if the tumor tested positive with high levels of Ki-67, the risk of recurrence was higher than average.
Do I Need The Ki-67 Tumor Marker Test?
If your cancer appears to be aggressive, your doctor may order this test to see if Ki-67 is affecting your tumor growth. Other tests must also be done for hormone receptors, HER2 - neu and metastasis, and these results, along with your Ki-67 Labeling Index (test score) will affect your treatment plan.
Benefits of The Ki-67 Tumor Marker Test
A breast tumor that scores high for Ki-67 is made of cells that are rapidly dividing and growing. Chemotherapy drugs target cells that are growing beyond the normal rate, and so these drugs can be effective on aggressive cancers. Knowing your Ki-67 score helps you and your doctor decide what treatment will work best for you.
Balancing Prognosis With Your Response to Treatment
A study in the Journal of Clinical Oncology found that tumors that had higher levels of Ki-67 had a good response to chemotherapy. This study noted that a high index of Ki-67 usually means a poor prognosis (shorter survival), but if the cancer responds particularly well to appropriate chemotherapy, long-term survival is achievable. They also speculate that if the Ki-67 test were done according to consistent standards, the results of a Ki-67 test might be helpful in determining whether or not neoadjuvant chemotherapy (given before surgery) would be effective for some tumors.
Ki-67 and Other Cancers
Ki-67 is found in several types of cancer, some of which are breast, bladder, brain, colon, and prostate cancer.

[DianneS]

Thank you Joe for your reply. I assume that I can get my tumour retested, tho this may not have much advantage since I have already gone through chemo. However I would still like it retested and have my ER and PR status reevaulated.

If a tumor is grade 3 don't they almost always have a high Ki-67 score? Mine was grade 3.

Thank you again,
Diannes

[Karen Wheel]

Thank you for asking!!! As I had did a bunch of searches trying to figure out this (about 3 weeks ago)- and just came up with a little information that I thought that meant that the cancer was more aggressive ....?
This info really helped me .... as I am -
Ki67 (MIB-1) positivia 30%.

AND - I only had a 1.5 cm tumor - Stage 1 .... so now I might be more nervous about this ---ugh! ????

Its now back on my list to talk to my Oncologist about (UGH! Its a challenge as my Italian is okay for getting around -but in medical terms it's not so great! --- my doc says she speaks English - but we end up speaking Italian! UGH!)

Thanks though, we need to look at all the information, and somehow figure out what it means.
Karen

[Lani]

a simplified way to look at it is as a marker of how quickly growing a cancer is. It is reported as a percentage which represents the percentage of cells in the field of view of the microscope that are undergoing cell division at any one time. The higher the percentage, the faster growing the tumor.

[norwegian]

Knowing about the KI67 score is not good for many of us. To me it will be very scaring to have get the information of having a high score.
In my opinion we do not need absolutely every information about aggressiveness, prognosisis, possibilities and so on. Being a HER2 woman with a grade 3 is enough to cope with already.

May be I will change my mind about this later, but right now I'm not ready for such information.