Table 1 Overview of all PD-L1 studies in IBC and their key findings. NACT neo-adjuvant chemotherapy, IHC immunohistochemistry, TMA tissue microarray, TC tumour cell, IC immune cell, N+ lymph node-positive disease, pCR pathological complete response, NR not reported, OS overall survival, DFS disease-free survival, sTIL stromal tumour-infiltrating lymphocytes, ER oestrogen receptor, T/NB tumour/normal breast ratio, TN triple negative
First author (year, country) | No. | Population | Detection method | AB clone | Cutoff for PD-L1+ | Positivity rate | Associated clinical and pathological variables | Associated outcome variables |
|---|---|---|---|---|---|---|---|---|
He et al., [17] (2018, USA) | 68 | Post NACT TN: 19/65 | IHC TMA [3] | 28-8 | ≥ 1% TC | 25/68 (36.8%) | / | Worse OS (P = 0.042) |
Arias-Pulido et al. [16] (2018, Algeria) | 221 | Pre NACT TN: 44/221 | IHC TMA [2] | SP142 | ≥ 5% TC and IC | TC: 18/221 (8.1%) IC: 146/221 (66.1%) | TC: N+, CD20+ TIL, pCR IC: grade 3, CD20+ TIL | IC: better DFS (P = 0.035) |
Reddy et al. [18] (2017, USA) | 14 | Pre NACT TN: - | IHC Biopsy | NR | NR (TC) | 3/14 (21.4%) | NR | NR |
Hamm et al. [19] (2016, USA) | 12 | Pre NACT TN: - | IHC Biopsy | E1LN3 | H-score (TC and IC) | TC: 4/12 (33.3%) IC: 8/12 (66.7%) | NR | NR |
Bertucci et al. [15] (2015, France) | 112 | Pre NACT TN: 28/112 | mRNA | / | T/NB ≥ 2 | 42/112 (37.5%) | ER negativity, basal and HER2+ subtype, cytotoxic T cell response, pCR | / |
Discovery cohort (Belgium) | 105 | Pre NACT TN: 23/105 | IHC Biopsy | SP142 | ≥ 1% tumour area (TC and IC) | TC: 2/105 (1.9%) IC: 45/105 (42.9%) | IC: sTIL, pCR | / |
Validation cohort (France) | 62 | Pre NACT TN: 12/62 | IHC Biopsy | SP142 | ≥ 1% tumour area (TC and IC) | TC: 0/62 (0%) IC: 24/62 (38.7%) | IC: sTIL | / |