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Poster display session

2570 - PD-L1 expression in TNBC: a predictive biomarker of response to neoadjuvant chemotherapy?

Date

11 Sep 2017

Session

Poster display session

Presenters

Andrea Botticelli

Citation

Annals of Oncology (2017) 28 (suppl_5): v22-v42. 10.1093/annonc/mdx363

Authors

A. Botticelli1, B. Cerbelli2, A. Pernazza2, C.E. Onesti1, P. Sciattella3, L. Costarelli4, M. Monti2, D. Campagna4, F. Mazzuca1, L. Fortunato5, P. Marchetti1, G. D'Amati2

Author affiliations

  • 1 Clinical And Molecular Medicine, Sapienza, University of Rome , Azienda Ospedaliera St. Andrea, 00189 - Roma/IT
  • 2 Radiological, Oncological And Pathological Science, Sapienza University of Rome,, 00100 - rome/IT
  • 3 Statistical Sciences, Sapienza University of Rome,, 00100 - rome/IT
  • 4 Pathology, San Giovanni Addolorata Hospital, 00100 - rome/IT
  • 5 Surgery, San Giovanni Addolorata Hospital, 00100 - rome/IT
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Resources

Abstract 2570

Background

Immune system plays an important role in tumor surveillance and escape. Recently tumor infiltrating lymphocytes (TILs) have been proposed as a predictive biomarker for clinical outcome and pathological response (pR) after neoadjuvant (neoadj) chemotherapy (CT) in breast cancer. PD-L1 is expressed in about 20% of TNBC, suggesting the possibility of being a therapeutic target for this subtype of cancers. Here we studied the association between PD-L1 expression and pR in TNBC.

Methods

We enrolled 54 pts who had received neoadj CT (EC for 4 cycles followed by Paclitaxel q21 for 4 cycles) between Jan 2008 and Dec 2016 at Policlinico Umberto I and San Giovanni Hospital of Rome. We performed IHC for CD20, CD3, CD4, CD8, CD68, N-CAM and PD-L1 (Ventana SP142 clone) in basal paraffin-embedded biopsies. PD-L1 expression on tumor cells was evaluated both qualitatively (membrane staining intensity 0 to 3+) and quantitatively (% of positive cells.). The percentage of TILs positive for PD-L1 was also recorded. Statistical analysis was performed with T di Student test and χ2 test.

Results

We enrolled 54 pts (median age: 50 y; range 28-75) affected by TNBC: 51 ductal (94.4%), 2 metaplastic (3.7%), 1 lobular (1.9%). The clinical stage before neoadj CT was as follow: 12.9% cT1 (7 pts), 72.2% cT2 (39 pts), 3.7% cT3 (2 pts), 1.85% cT4 (1 pt) and 5.5% cTx (3 pts). 23 pts were cN + (42.5%). After neoadj CT 30 pts underwent mastectomy (55%) and 24 conservative surgery (45%). 19 pts (35%) showed pCR. No significant associations were found between pR and cT, cN, age, histotype and KI-67. In 64.8% of basal biopsies (35 pts) PD-L1 was not detected on tumor cells and in 18.5% (10 pts) it was absent in the immune infiltrate. PD-L1 expression was detected in > 25% of tumor cells in 4 pts, all of which showed pCR (p = 0.024). No associations between intensity of membrane staining and pR were detected (p = 0.7). The immune infiltrate was characterized mostly by the presence of CD3+ CD8+. No statistically significant associations between and PD-L1 expression on immune infiltrate were detected.

Conclusions

Basal PD-L1 expression on cancer cells was associated with a better pR in TNBC undergoing neoadj CT. The introduction of anti PD-1/PD-L1 therapy in this setting of pts could lead to interesting results.

Clinical trial identification

Legal entity responsible for the study

Sapienza University of Rome

Funding

None

Disclosure

P. Marchetti: Advisory board and meeting with Pfizer, Roche, Novartis, MSD, Bristol-Myers Squibb, Ipsen, AstraZeneca, Boehringer Ingelheim. All other authors have declared no conflicts of interest.

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