الفهرس 
NTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Breast cancer remains an important worldwide health concern as a major cause of morbidity and mortality among females.
Ongoing research has been conducted to identify new markers that could help in accurate prediction of BC outcome besides the conventionally used prognostic factors, and would concurrently serve a possible target for immunotherapy.
A major immunomodulator, PD-L1 has been proposed as potential biomarker. The objective of this work is to determine the expression pattern of PD-L1 in specimens of invasive ductal carcinomas in correlation with other recognized clinicopathological parameters to ascertain its potential applicability as a predictor of tumor behavior.
Histological examination was done, IHC was reviewed for 50 IDC-NST specimens concerning ER, PR, HER2, ki67 while PD-L1 staining was performed. This study enrolled patients with a mean age of 52.66 ±9.84, 66% of them had no family history of cancers, 56% were left sided and 72% were unifocal. Grade I tumors represented 2% of the tumors while grade II and grade III represented 72% and 26% respectively. Of the 50 specimens, twelve of the tumors were T1, 28 tumors were T2, 9 tumors were T3 and only 1 tumor revealed intra-epidermal invasion thus being T4. Twelve of the studied cases (24%) had no metastatic LN while 38 cases (76%) ranged from N1 to N3. Tumors with stages I-II represented 44% while the majority (52%) were stage III. LVI was noted among most of the cases (98%). Lymphocytic infiltration was observed to be moderate to dense in 56% of tumors while the remaining 44% had no or mild lymphocytic infiltrates. ER/PR positivity was detected in 60% of tumors whereas HER2 positivity was detected in 38% of tumors. Ki67 was low in 64% of the cases. HR+/HER2- and HR+/HER2+ cases represented 30% each, 8% were HR-/HER2+ and 32% of the cases had TN profile. Only 2 cases (4%) revealed recurrence or metastasis from the start. PD-L1 expression was detected only in 3 cases (6%) who were >50 years old patients, T3, N2 or N3, stage III, grade III, TNBC tumors which showed LVI
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as well as moderate to dense TIL. PD-L1 expression was significantly associated with high tumor grade (p=0.015), larger tumor size (p=0.006), tumors with high ki67 (p=0.042) and TNBC (p=0.029). It was then chosen to further analyze certain parameters among the TNBC subgroup. These included tumor size, LN status, stage, tumor grade and ki67. The results showed only tumor size to be positively correlated with the expression of the marker (p=0.007).
In the overall cohort, PD-L1 was not significantly associated with any of the remaining parameters including patient age, family history, side and number of tumors, LVI, TIL, LN status, stage, HR, HER2 and recurrence/metastasis status.