[174] Breast Cancer Molecular Subtypes Treated with Neoadjuvant Chemotherapy (NACT): Correlation with Grade, Ploidy, Ki67 and p53 Expression

A Cockburn, J Han, D Euhus, Y Peng, VR Sarode. UTSW, Dallas, TX

Background: The identification of tumor characteristics that can predict response to NACT is critical for determining outcome and response to chemotherapy in patients with breast cancer. The aim of this study is to determine if there is an association between molecular subtypes of breast cancer and pathologic response, grade, ploidy, ki67 and p53 expression.
Design: Patients with a diagnosis of invasive carcinoma on core biopsies who underwent NACT between the years 2000-2009 were identified in the electronic medical record and retrospectively analyzed. Clinical and pathologic data such as; race, age, clinical stage, tumor size, chemotherapy regimen, histologic type, tumor grade, and size of residual tumor was obtained. Tumor response was evaluated using Sataloff's classification: pathologic complete response (pCR); > 50%; < 50% reduction in tumor size and no therapy effect. Biomarkers (ER, PR, Her2Neu, ploidy, Ki67 and p53) were performed in a routine fashion and analyzed by the DAKO ACIS III image analyzer. Her2 positive cases were confirmed by FISH analysis. Tumors were stratified into four molecular subtypes; ER+PR±Her2-, ER+PR±Her2 +, ER-PR-Her2+, ER-PR-Her2-.
Results: There were 175 cases, of which 43 were excluded due to incomplete data. Age range was 21–77 yrs (mean 47). Of the 132 cases, 2 (1%) were stage I, 40 (31%) stage II, 47 (36%) stage III, 23 (17%) stage IV and 20 (15%) not known. Histologic types were ductal (95%) and lobular (5%) carcinoma. Chemotherapy regimens included adriamycin and cytoxan (AC) followed by taxanes in 62%, AC in 15%, Herceptin in 13%, 10% patients also received carboplatin, Gleevec and Gemzar. Complete response was noted in 18.9%.

Tumor profileER+PR±Her2- (50)ER+PR±Her2+ (17)ER-PR-Her2+ (26)ER-PR-Her2- (39)
Grade 1 (1)1000
Grade 2 (61)331387
Grade 3 (70)1641832
Aneuploid/multiploid (95)28142528
Diploid (27)19314
Ki67∗38.39±3.6931.82±4.8955.19±5.466.0±3.59
P53∗12.6±3.9822.1±8.6340.32±8.6255.71±7.35
pCR (25)53107
> 50% (46)206614
< 50% (31)104413
No response (31)15466
∗ mean±SEM; (total number)


Conclusions: Molecular subtypes of breast cancer can predict response to NACT. Of the tumors with pCR, 68% were of the Her2+ and triple negative subtypes. These tumors were likely to be high grade with high ki67 and p53 expression. Non-responsive tumors were likely to be hormone receptor positive, diploid with a lower Ki67 and p53 expression.
Category: Breast

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 60, Tuesday Morning

 

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