Identification of the entosis stages in situ in lung cancer tissue and their changes after neoadjuvant chemotherapy

Objective. To identify in situ stages of entosis in non-small cell lung cancer (NSCLC) tissue and to assess the impact of neoadjuvant chemotherapy (NACT) on their frequency. Material and methods. The study included 9 patients with morphologically verified NSCLC (stage T1—2N0—1M0—1) classified according to the WHO classification (2021). Four patients received NACT (vinorelbine + carboplatin), while five underwent surgery without prior therapy. Histological specimens were examined using Whole Slide Imaging (Pannoramic Mirax Midi, Carl Zeiss, Germany) and analyzed with Panoramic Viewer software. Entotic events were identified according to Mackay’s criteria. Statistical analysis was performed using the Mann—Whitney U test. Results. All five lysosomal stages of entosis were successfully identified in situ. Stage II was the most frequently observed. In patients treated with NACT, Stage III was more common, suggesting a slowing of this phase, while the frequency of Stage V was significantly lower (p=0.01). A trend toward an overall increase in entotic events after NACT was noted; however, when normalized to tumor section area, no significant differences between groups were detected. For the first time in situ, variants of entomammoptosis were identified, including binucleated “loser” cells and mitosis of the internalized cell. Conclusion. Neoadjuvant chemotherapy does not increase the overall frequency of entosis in NSCLC tissue but alters the distribution of stages, prolonging Stage III and reducing the completion of the process at Stage V. The results expand current understanding of the role of entosis in tumor cell adaptation and the development of drug resistance in NSCLC.