Tumor mutational burden on cytological samples: A pilot study

Valerio Gristina, Antonio Russo, Albino Eccher, Umberto Malapelle, Antonino Iaccarino, Danilo Rocco, Caterina De Luca, Roberta Sgariglia, Pasquale Pisapia, Ilaria Girolami, Gianluca Gragnano, Mariantonia Nacchio, Mariacarolina Micheli, Gianluca Russo, Francesco Pepe, Rossella Tufano, Caterina De Luca, Antonino Iaccarino, Pietro Micheli, Giancarlo Troncone

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Background: Immune-checkpoint inhibitors (ICIs) represent an important treatment option for patients who have advanced stage non–small cell lung cancer (NSCLC). Currently, evaluation of the expression level of programmed death-ligand 1 (PD-L1) has proven highly successful as a positive predictive biomarker for ICIs. In addition to PD-L1, other promising predictive biomarkers are emerging, including high tumor mutational burden (TMB-H). However, measuring TMB-H remains challenging for several reasons, among which is the difficulty in obtaining adequate tissue material from NSCLC patients. There are no data in the current literature regarding the possibility of adopting cell blocks (CBs) for TMB evaluation; therefore, our goal was to evaluate the feasibility of analyzing TMB on CBs. Methods: For evaluation of differences in run metric parameters, 8 pairs of histological and CB samples from patients with NSCLC were analyzed using the Oncomine Tumor Mutational Load Assay on Ion Torrent S5 GS next-generation sequencing (NGS) platform. Results: Most CBs (6/8, 75.0%) were successfully analyzed by adopting the broad NGS panel approach. CBs provided results similar to those obtained on histological matched specimens in terms of median total reads (7207048.80 vs 7558817.80), median mapped reads (7075753.83 vs 7513822.00), median read lengths (115.50 vs. 113.00), median percentage of reads on-target (97.49% vs. 98.45%), median average reads per amplicon (454.67 vs 476.14), and median uniformity of amplicon coverage (83.52% vs 84.13%). Conclusion: In this pilot study, we demonstrated the technical feasibility of assessing TMB on CBs.
Original languageEnglish
Number of pages8
JournalCancer cytopathology
Publication statusPublished - 2020

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research


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