So confused about Luminal A and Luminal B

weesa

And the more I read, the more confused I get. Seems to me it would behoove all of us er, pr positive ladies here to know where we fall. For instance, if you are having trouble taking an AI and your onc wants you to continue on after 5 years, it might help your decision process if you knew you were Luminal B, which carries a worse prognosis that Luminal A.

I am highly er, pr positive (95 and 90 percent respectively) her-2 negative, with a very high ki-67--70 percent. My mitotic rate was a one. I am grade 2. Which am I--Luminal A or Luminal B?

I am hoping somebody out there can tell me.

Momine

Weesa, from what I read the last few days, the divider is the Ki-67 score. I think that "low" Ki-67 is anything below 30%, but I am not sure that is set in stone. With your stats, as far as I can understand you would be a 'B'. However, it seems like something to ask a doctor.

new_direction

I think i read somewhere that luminal B was above 15/20. Mine was 30 and think I am luminal B.

From this article: "Difference between Luminal A and Luminal B Subtypes According to Ki-67, Tumor Size, and Progesterone Receptor Negativity Providing Prognostic Information"
Luminal A – ER positive, HER2 negative, Ki-67 low, and PR high; Luminal B (HER2 negative) – ER positive, HER2 negative, and either Ki-67 high or PR low; Luminal B-like (HER2 positive) – ER positive, HER2 overexpressed or amplified, any Ki-67, and any PR; HER2 positive – HER2 over-expressed or amplified, ER and PR absent; and triple negative – ER and PR absent and HER2 negative...
...If the Ki-67 labeling index and/or nuclear grade was determined, the Luminal A subtype was also defined to a low Ki-67 labeling index (<14%) and/or nuclear grade 1 or 2. ER and PR positivity was confirmed by immunohistochemistry (IHC); greater than 1% of tumor cells staining positive was considered to be positive. A HER2-negative status was confirmed by the IHC (with 0, 1+, and 2+ scores indicating no cells stained, <10% of cells have membrane staining and >10% of cells with a low or medium membrane staining, respectively). Tumors that were 2+ by IHC were also examined by fluorescence in situ hybridization (with an amplification ratio <2.0, indicating a negative status). The Ki-67 labeling index was determined by IHC. Figure 1 shows the Ki-67 antigen staining in both its ER- and PR-positive sections.

ruthbru

weesa, there is a good discussion about Luminal A & B going on in the forum 'Just Diagnosed with a Recurrence', under the topic 'Is it realistic to think you'll never get a recurrence?' I will bump it right now.