Assessing the relationship between tumor-infiltrating lymphocytes and PD-L1 expression in triple negative breast cancer: Identifying optimal TILs cut-off value for pathologic reporting.

BACKGROUND: Triple Negative Breast Cancer (TNBC) presents diagnostic complexities, particularly in evaluating Tumor-Infiltrating Lymphocytes (TILs) and Programmed Death-Ligand 1 (PD-L1) expression. This study aimed to identify optimal TILs percentage cut-offs predictive of PD-L1 expression and to investigate the relationship between TILs, PD-L1, and tertiary lymphoid structures (TLSs). METHOD: Analyzing 141 TNBC cases, we assessed TILs, PD-L1 expression (clones 22C3 and SP142), and TLS presence. RESULTS: We identified TILs cut-offs (<20 %, 20-60 %, ≥60 %) correlating with PD-L1 expression. TILs <20 % rarely express PD-L1 with either 22C3 or SP142 clones. TILs ≥60 % demonstrate PD-L1 expression across both clones. TILs within the 20-60 % range correlate with PD-L1 expression using the SP142 clone, but not 22C3. Evaluating TILs solely at the tumor edge led to inaccuracies, highlighting the need for overall assessment of TILs throughout the entire lesion. TLS presence correlated with higher TIL percentages and PD-L1 expression, particularly with SP142. Discrepancies between 22C3 and SP142 clones (15 % vs. 50 % positivity, respectively) underscored the variability in PD-L1 detection. CONCLUSION: This study identifies TILs cut-offs predictive of PD-L1 positivity, suggesting the need for institutions to tailor these thresholds based on the selected PD-L1 clone and treatment. Evaluating TILs solely at the tumor edge may overlook the complexity of tumor immune infiltration. While TLS presence correlates with higher PD-L1 expression, particularly with the SP142 clone, its exact predictive value for PD-L1 remains to be clarified. The SP142 clone exhibits higher positivity rates compared to 22C3.

Non-neurotoxic activity of Malayan krait (Bungarus candidus) venom from Thailand

Background: Envenoming by kraits (genus Bungarus) is a medically significant issue in South Asia and Southeast Asia. Malayan krait (Bungarus candidus) venom is known to contain highly potent neurotoxins. In recent years, there have been reports on the non-neurotoxic activities of krait venom that include myotoxicity and nephrotoxicity. However, research on such non-neurotoxicity activities of Malayan krait venom is extremely limited. Thus, the aim of the present study was to determine the myotoxic, cytotoxic and nephrotoxic activities of B. candidus venoms from northeastern (BC-NE) and southern (BC-S) Thailand in experimentally envenomed rats. Methods: Rats were administered Malayan krait (BC-NE or BC-S) venom (50 g/kg, i.m.) or 0.9% NaCl solution (50 L, i.m.) into the right hind limb. The animals were sacrificed 3, 6 and 24 h after venom administration. The right gastrocnemius muscle and both kidneys were collected for histopathological analysis. Blood samples were also taken for determination of creatine kinase (CK) and lactate dehydrogenase (LDH) levels. The human embryonic kidney cell line (HEK-293) was used in a cell proliferation assay to determine cytotoxic activity. Results: Administration of BC-NE or BC-S venom (50 g/kg, i.m.) caused time-dependent myotoxicity, characterized by an elevation of CK and LDH levels. Histopathological examination of skeletal muscle displayed marked muscle necrosis and myofiber disintegration 24 h following venom administration. Both Malayan krait venoms also induced extensive renal tubular injury with glomerular and interstitial congestion in rats. BC-NE and BC-S venoms (1000.2 g/ mL) caused concentration-dependent cytotoxicity on the HEK-293 cell line. However, BC-NE venom (IC50 =8 ± 1 g/mL; at 24 h incubation; n = 4) was found to be significantly more cytotoxic than BC-S venom (IC50 =15 ± 2 g/mL; at 24 h incubation; n = 4). In addition, the PLA2 activity of BC-NE venom was significantly higher than that of BC-S venom...

Non-neurotoxic activity of Malayan krait (Bungarus candidus) venom from Thailand

Envenoming by kraits (genus Bungarus) is a medically significant issue in South Asia and Southeast Asia. Malayan krait (Bungarus candidus) venom is known to contain highly potent neurotoxins. In recent years, there have been reports on the non-neurotoxic activities of krait venom that include myotoxicity and nephrotoxicity. However, research on such non-neurotoxicity activities of Malayan krait venom is extremely limited. Thus, the aim of the present study was to determine the myotoxic, cytotoxic and nephrotoxic activities of B. candidus venoms from northeastern (BC-NE) and southern (BC-S) Thailand in experimentally envenomed rats. Methods: Rats were administered Malayan krait (BC-NE or BC-S) venom (50 µg/kg, i.m.) or 0.9% NaCl solution (50 µL, i.m.) into the right hind limb. The animals were sacrificed 3, 6 and 24 h after venom administration. The right gastrocnemius muscle and both kidneys were collected for histopathological analysis. Blood samples were also taken for determination of creatine kinase (CK) and lactate dehydrogenase (LDH) levels. The human embryonic kidney cell line (HEK-293) was used in a cell proliferation assay to determine cytotoxic activity. Results: Administration of BC-NE or BC-S venom (50 µg/kg, i.m.) caused time-dependent myotoxicity, characterized by an elevation of CK and LDH levels. Histopathological examination of skeletal muscle displayed marked muscle necrosis and myofiber disintegration 24 h following venom administration. Both Malayan krait venoms also induced extensive renal tubular injury with glomerular and interstitial congestion in rats. BC-NE and BC-S venoms (100­0.2 µg/ mL) caused concentration-dependent cytotoxicity on the HEK-293 cell line. However, BC-NE venom (IC50 =8 ± 1 µg/mL; at 24 h incubation; n = 4) was found to be significantly more cytotoxic than BC-S venom (IC50 =15 ± 2 µg/mL; at 24 h incubation; n = 4). In addition, the PLA2 activity of BC-NE venom was significantly higher than that of BC-S venom. Conclusions: This study found that Malayan krait venoms from both populations possess myotoxic, cytotoxic and nephrotoxic activities. These findings may aid in clinical diagnosis and treatment of envenomed patients in the future.(AU)