Table 1. Summary of retrospective studies which evaluated inter-tumor heterogeneity of PD-L1 expression status between primary lung tumors and lymph node metastases.
| Year | Authors | Histology | N | Antibody | Findings | Ref. |
|---|---|---|---|---|---|---|
| 2015 | Kim MY, et al. | SQ | 77 | E1L3N | PD-L1 expression status (positive vs. negativea) was discordant in 30% of patients | (13) |
| PD-L1 was positive in PTs/negative in LNs in 19%, and negative in PTs/positive in LNs in 11% of patients | ||||||
| 2017 | Uruga H, et al. | AD | 109 | E1L3N | Concordance rates: 82–85%b in comparing PTs vs. N1; 62–90%b for PTs vs. N2 and 83–100%b for N1 vs. N2 | (14) |
| Change in predominant histologic pattern (PTs vs. LNs) was associated with discordance of PD-L1 status for PTs vs. LNs | ||||||
| PD-L1 was positive in PTs/negative in N1 in 9–18%b of samples and negative in PTs/positive in N1 in 0–6%b of samples. PD-L1 was positive in PTs/negative in N2 in 3–19%b of samples and negative in PTs/positive in N2 in 6–19%b of samples | ||||||
| 2017 | Sakakibara R, et al. | AD | 33 | EPR1161 | Correlation between PD-L1 positivity in PTs vs. LNs was r=0.49 | (15) |
| SQ | 9 | |||||
| Others | 5 | |||||
| 2018 | Liu Y, et al. | ASC | 38 | E1L3N | PD-L1 expression was compared for paired histological components. In SQ components, 80–90%c showed concordance, while for AD components, 74–78%c showed concordance | (16) |
| In AD components, difference in predominant histologic patterns were associated with differences in PD-L1 expression | ||||||
| 2019 | Xu H, et al. | AD | 37 | 22C3 | Concordance rates: 60–68%b in comparing PTs vs. N1 | (17) |
| SQ | 39 | Concordance rate: 46%d in comparing N1 vs. N2 | ||||
| PD-L1 was positive in PTs/negative in N1 in 7–13%b of samples and negative in PTs/positive in N1 in 0–13%b of samples | ||||||
| 2019 | Haragan A, et al. | AD | 63 | SP263 | Median difference in TPS for PTs vs. LNs: 10% (range, 1–94%); discordance was present in 53% of cases. This difference moved the TPS across a clinical guidance cut-off in 23% of cases | (18) |
| SQ | 44 | Concordance rate of TPS for LNs (N1 vs. N1 or N2) was 83% | ||||
| PD-L1 expression was higher in PTs than in LNs in 28% of samples and higher in LNs than in PTs in 25% of samples | ||||||
| 2019 | Saito Y, et al. (present) | AD | 27 | 22C3, 28-8 | Concordance rates: 51–71%e (22C3) and 49–71%e (28-8) in comparing PTs vs. LNs. Concordance rates were 29% (22C3) and 31% (28-8) when PD-L1 status was classified into three categoriesf | (4) |
| SQ | 6 | PD-L1 status was higher in PTs than in LNs in 51% (22C3) and 46% (28-8) of samples and higher in LNs than PTs in 20% (22C3) and 23% (28-8) of samples | ||||
| Other | 2 |
a, PD-L1 status was defined to be positive if 10% or more tumor cells had membrane staining; b, different cut-off values (1%, 5%, and 50%) were used for the comparison; c, different cut-off values (1% and 5%) were used for the comparison; d, 1% of cut-off value was used for the comparison; e, different cut-off values (1% and 50%) were used to calculate the concordance rates; f, PD-L1 status was classified into <1%, 1–49%, and 50% or higher. PTs, primary tumors; LNs, lymph nodes; N1, N1 lymph nodes; N2, N2 lymph nodes; AD, adenocarcinoma; SQ, squamous cell carcinoma; ASC, adenosquamous cell carcinoma.