الفهرس 
Association of PD-L1 Expression with Neoadjuvant Chemotherapy Response in Different Molecular Subtypes of Invasive Breast Carcinoma
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Abstract
Although breast carcinoma had many targeted biomarkers
for its treatment, it is a heterogenous disease with different outcomes and
needs new markers especially for the triple negative group when estrogen,
progesterone receptors and Her2/neu are negative. Programmed death-ligand
1 (PD-L1) is a new target with unclear role.
The aim of this study was to examine the prevalence of PD-L1 in locally
advanced invasive breast carcinoma and to elucidate its relation to tumorinfiltrating lymphocytes, breast carcinoma subtypes, established
clinicopathological factors, pathological therapy response after neoadjuvant
chemotherapy, disease-free survival and overall survival.
Material and Methods: One hundred and five cases of locally advanced
invasive breast carcinoma (stages IIB, IIIA, IIIB and IIIC) were evaluated
for age, grade, tumor size, stage and node status (clinically before therapy
and pathologically after therapy). The cases were retrieved
immunohistochemically for estrogen receptor, progesterone receptor,
Her2/neu and Ki-67. PD-L1 immunostaining was done and analyzed for all
studied cases. Also, pretherapy tumor-infiltrating lymphocytes (TILs)
density as well as TILs change after therapy were calculated and analyzed.
Pathological therapy response was evaluated in all studied cases by different
three pathological systems (Residual Cancer Burden, Miller-Payen grading
system and Sataloff’s system). PD-L1 expression was correlated with
pretherapy TILs density, TILs change, pathological therapy response,
histopathological factors, breast cancer subtypes, 7-years DFS and overall
survival.
Results: PD-L1 was expressed in 32.4% of the studied cases. It was
significantly associated with old age group, high grade tumors and high
density (pretherapy) TILs. It was also expressed in a significant number of
triple negative breast carcinoma (44.4%). PD-L1 negative breast cancer
cases have better prognosis than those with PD-L1 positive breast cancer
with statistically non-significant P value. There was no significant relation
between PD-L1 and pathological therapy response, although, it revealed
more expression in cases with complete therapy response. High change in
TILs after therapy was strongly associated with complete and marked
therapy response.
Conclusion: Although the impact of PD-L1 on locally advanced breast
cancer outcomes had not been clearly established, this result may provide
evidence that PD-L1 is a bad prognostic and predictive marker. PD-L1 could
be a new target for the treatment of patients with high grade breast
carcinoma and TNBC group.