Luminal A vs Luminal B

Anonymous

Can someone please tell me the difference between Luminal A and Luminal B? Would the type that I have be noted somewhere on the pathology report?

Thanks in advance!

wintersocks

Hello kayb

Thanks for this info.

May I ask if i am ER+ only does that make it luminal A?

What differences does it make if It is A or B?

Thanks

doxie

Luminal B also include ER+, very low PR+ and HER2 negative, along with high Ki 67. The PR and Ki67 is not standardized. Very roughly around 5% or less for PR and more than 14-20 for Ki67.

Meow13

I guess I am in the luminal B category my pr status was less than 1 %. I am so tired of thinking about the cancer I had or is lurking.

Gohan1983

The main difference between those 2 subtypes is genomic profile, not some 3 or 4 IHC proteins (ER, PR, HER-2 and Ki67). Luminal B generally has high expression of genes associated with proliferation (MKI67, MYBL2, FGFR1) and somewhat lower expression "estrogen related" genes like: ESR1, FOXA1, GATA3. Luminal B is usually HER-2 negative (but 30% of LumB are also HER-2 positive), but more often has high histologic grade (G3) than LumA (which hardly ever is Grade3). The most frequent morphologic subtypes which show LumB profile are: Invasive Ductal not otherwise specified, Invasive Micropapillary, Invasive Ductal with Neuroendocrine Differentiation, Invasive Lobular Pleomorphic and Invasive Signet-Ring Cell Carcinoma. Luminal B according to IHC profile is all tumours which ER-positive and PR positive/weakly positive/negative and/or Ki67 > 20% and/or HER-2 overexpression. Grade 3 Luminal tumours almost always belong to LumB profile.

gerrib

I am about 6 weeks out for umx for 2nd diagnosis of BC. I am second guessing my decision not to have chemo. The MO said that it would give me a 5% improvement in survival rate. This time I had ILC, The nodes were neg and size was 2cm. But the tumour was somewhat unusual. It was only weakly Er+ (30%) Pr neg and the Ki67 was 20%. It was characterised as pleomorphic which sounds scary when you Google, but neither the surgeon or MO seemed too concerned about 'pleomorphic', saying it was just the shape of the cells. The surgeon said he wouldn't have chemo if it was him and I came away confident that I would not require chemo. Then I went to MO and she gave me 2 options AI alone or chemo followed by AI. I dismissed the chemo option as to me 5% improvement in survival rate did not seem great to me for the discomfort associated with chemo.. But now I have become concerned about the Ki67( mine was 20%) and the only weakly positive Er+ and neg Pr. HER is neg. I am 65. my MO did not seem concerned that I decided not to have chemo. and of course I would prefer not to. I am in Australia and Oncotype testing is not done here.

I would welcome any comments about whether I should reconsider my decision not to have chemo. I have commenced Arimidex and so far (3 weeks) no SEs.

I am posting in this thread because from what I have read my tumour is probably Luminal B?? My age, being 65, is significant in my decision to probably forgo chemo. I am seeing the MO again on Monday to get a few more details about her estimate of my distant recurrence rate with and without chemo.

Thanks

Gerri