PD-L1 (SP142) testing is concordant between Benchmark Ultra and Bond-III stainers.

BACKGROUND: Atezolizumab is an inhibitor of programmed death-ligand 1 (PD-L1), used to treat advanced or metastatic bladder cancer, and in trials for non-invasive disease. In order to be eligible for treatment, patients require a PD-L1 immune cell score ≥ 5%, using the Ventana SP142 PD-L1 assay. Many laboratories do not have access to the required Ventana Benchmark Ultra stainer, and it is unclear if the assay performs similarly on other stainers. In this study, we compare SP142 assay results between Ventana Benchmark Ultra and Leica Bond-III stainers. METHODS: Serial sections of 90 samples of transurethral bladder resections (comprising 51 pTaHG, 8 pTis, 18 pT1, 10 pT2 tumors) were stained using the SP142 PD-L1 antibody on Ventana Benchmark Ultra and Leica Bond-III stainers, manually scored, and compared using accuracy and Cohen's kappa measures. RESULTS: Both devices yielded highly concordant PD-L1 immune cell scores (accuracy 0.84, Cohen's κ 0.732). Moreover, we found similar tumor cell (TC) PD-L1 scores using both stainers, and a trend towards greater TC scores in pT2 stage samples (p = 0.05). CONCLUSION: This study is the first to compare the SP142 antibody in bladder cancer on two different stainers. Our results indicate that both Benchmark Ultra and Bond-III stainers yield highly concordant results using the SP142 PD-L1 antibody.

Smooth muscular layer: A new helpful criterion to reclassify tumor deposits into metastatic lymph nodes in patients with colo-rectal adenocarcinoma.

CONTEXT: The origin of tumor deposit in colorectal cancer is still unknown, and currently there is no single morphological feature to distinguish a metastatic lymph node from a tumor deposit. Histologically, the normal lymph node capsule and trabeculae contain a smooth muscular layer, which when present in extramural deposits would strongly suggest their lymph node origin. OBJECTIVE: We analyze the value of the smooth muscular layer criterion in reclassifying tumor deposit into metastatic lymph node. DESIGN: A total of 458 colo-rectal carcinomas surgical specimens treated or not by neoadjuvant (radio)chemotherapy were retrospectively included. Harvested tumor deposits were analyzed by Hematoxylin and Eosin and elastin staining on 10 consecutive serial sections and by α- smooth muscle actin immunostaining. RESULTS: A total of 129 tumor deposits were identified. 77 (60%) tumor deposits were reclassified into metastatic lymph node, of which 63 (49%) presented a smooth muscular layer on the initial Hematein Eosin staining and/or after serial tissue sections, confirmed by positive α-smooth muscle actin immunostaining in 43 out of 45 cases (90%). Fourteen (18%) additional tumor deposits were reclassified into metastatic lymph node by the appearance of lymphoid tissue after serial sections. CONCLUSIONS: The presence of a smooth muscular layer in a presumable tumor deposit is helpful in pointing out its lymph node origin in patients with colo-rectal carcinomas. This criterion could improve the inter-observer agreement of tumor deposit identification, allowing accurate nodal staging and better assessment of patient's prognosis.