Predictive value of primary tumor volume change during concurrent chemoradiotherapy in patients with unresectable stage III non-small cell lung cancer.

BACKGROUND AND PURPOSE: No established early biomarkers currently exist to predict responses during concurrent chemoradiotherapy (CCRT) in patients with unresectable non-small cell lung cancer (NSCLC). This study investigated the potential of gross tumor volume (GTV) and its changes during CCRT as predictors of survival outcomes. MATERIALS AND METHODS: We identified 227 patients with unresectable stage III NSCLC who underwent definitive CCRT followed by durvalumab between November 2018 and December 2022. GTV was defined as the volume of the primary tumor, assessed at two time points: before starting CCRT for initial planning (GTV1), and at the fourth week of CCRT for adaptive planning (GTV2). Both relative and absolute regressions between GTV1 and GTV2 were calculated. RESULTS: The median GTV1 volume was 90 mL (range, 5-840 mL), and the median GTV2 volume was 64 mL (range, 1-520 mL), resulting in median absolute and relative regressions of 18.6 mL and 25.0 %, respectively. Among the GTV parameters, relative GTV regression exhibited the strongest predictive value, with an area under the curve (AUC) of 0.804 for in-field progression and 0.711 for overall progression. The 1-year progression-free survival rates for the high (>30 %), intermediate (0-30 %), and low (≤0%) relative regression groups were 88.0 %, 62.6 %, and 14.3 %, respectively (p = 0.006 for high vs. intermediate; p < 0.001 for intermediate vs. low). Additionally, GTV2 volume demonstrated stronger associations with survival outcomes than GTV1 volume. CONCLUSION: Relative GTV regression was identified as a promising early predictor for patients with unresectable stage III NSCLC. Further development of a multi-parametric predictive model is warranted to guide patient-tailored therapeutic approaches.

Orthotopic model of pancreatic cancer using CD34+ humanized mice and generation of tumor organoids from humanized tumors.

In pancreatic cancer (PC) as intractable solid cancer, current research is focused mainly on targeted immunotherapies such as antibodies and immune cell modulators. To identify promising immune-oncological agents, animal models that recapitulate the essential features of human immune status are essential. To this end, we constructed an orthotopic xenograft model using CD34+ human hematopoietic stem cell-based humanized NOD scid gamma mouse (NSG) mice injected with luciferase-expressing PC cell lines AsPC1 and BxPC3. The growth of orthotopic tumors was monitored using noninvasive multimodal imaging, while the subtype profiles of human immune cells in blood and tumor tissues were determined by flow cytometry and immunohistopathology. In addition, the correlations of blood and tumor-infiltrating immune cell count with tumor extracellular matrix density were calculated using Spearman's test. Tumor-derived cell lines and tumor organoids with continuous passage capacity in vitro were isolated from orthotopic tumors. It was further confirmed that these tumor-derived cells and organoids have reduced PD-L1 expression and are suitable for testing the efficacy of specific targeted immunotherapeutic agents. These animal and culture models could facilitate the development and validation of immunotherapeutic agents for intractable solid cancers including PC.

1-Methylxanthine enhances the radiosensitivity of tumor cells.

PURPOSE: To determine the efficacy of a caffeine derivative 1-methylxanthine (1-MTX) in increasing radiosensitivity of cancer cells and elucidate the underlying mechanisms in vitro. MATERIALS AND METHODS: RKO human colorectal cancer cells carrying wild type protein 53 kDa (p53) were incubated with 3 mM 1-MTX for 30 min, exposed to 4 Gy ionizing radiation, and further incubated with 1-MTX for three days. The clonogenic cell death was determined, and the cell cycle distribution and apoptosis were studied with flow cytometry at different times after irradiation. The DNA double strand break (DNA DSB) was examined using phosphorylated Histone2A (gamma-H2AX) foci formation, and the expression/activity of checkpoint 2 kinase (Chk2), cell division cycle 25 (Cdc25) phosphatase and cyclin B1/Cdc2 kinase were also investigated using western blotting and in vitro kinase assays. RESULTS: The treatment with 3 mM 1-MTX increased the radiation-induced clonogenic and apoptotic cell death. The radiation-induced phosphorylation of Chk2 and Cdc25c and the radiation-induced increase in the cyclin B1/Cdc2 kinas activity were little affected by 1-MTX. The radiation-induced G2/M arrest was only slightly shortened and the expression of radiation-induced gamma-H2AX was markedly prolonged by 1-MTX. CONCLUSIONS: 1-MTX significantly increased the radiosensitivity of RKO human colorectal cancer cells carrying wild type p53 mainly by inhibiting the repair of radiation-induced DNA DSB without causing significant alteration in radiation-induced G2/M arrest. Such a radiosensitization occurred at 1-MTX concentrations almost non-toxic to the target tumor cells.