Expression of HIF‑α and their association with clinicopathological parameters in clinical renal cell carcinoma

Objectives

This study aimed to assess the cellular localization and expression levels of hypoxia-inducible factor (HIF) -α proteins (specifically HIF-1α, HIF-2α, and HIF-3α) that play a role in the hypoxia pathway and to determine their correlation with clinicopathological parameters and patient survival in renal cell carcinoma (RCC).

Materials and methods

Tissue microarray (TMA) with cores from 150 clear cell RCCs and 31 non-ccRCC samples. HIF-1α, HIF-2α, and HIF-3α antibodies were used for immunohistochemistry (IHC) of TMA to evaluate the cellular localization and expression levels of HIF-α proteins, specifically in relation to the hypoxia pathway.

Results

The expression levels of the HIF-α proteins were higher in the nucleus than in the cytoplasm. Furthermore, the nuclear expression levels of all HIF-α proteins were significantly higher in clear cell RCC (ccRCC) than in non-ccRCC. Cytoplasmic HIF-3α expression was also higher in ccRCC than in non-ccRCC, whereas cytoplasmic HIF-1α and HIF-2α expression levels were similar between the different RCC types. In ccRCC, nuclear HIF-1α expression levels correlated with both nuclear HIF-2α and HIF-3α levels, whereas cytoplasmic HIF-3α expression levels were associated with HIF-1α only.In non-ccRCC, there was a positive correlation observed between nuclear HIF-1α and HIF-3α expression, but no correlation was found with HIF-2α. In patients with ccRCC, the nuclear expressions of HIF-1α and HIF-3α was significantly associated with cancer-specific survival (CSS) in univariate analysis. This association was no longer evident in multivariate analysis. Notably, there was no correlation observed between nuclear HIF-2α expression and CSS in these patients. In contrast, cytoplasmic expression levels showed no association with CSS.

Conclusion

The expression levels of the three primary HIF-α proteins were found to be higher in the nucleus than in the cytoplasm. Furthermore, the results indicated that HIF-3α and HIF-1α expression levels were significant univariate factors associated with CSS in patients with clear cell RCC. These results highlight the critical role that HIF-3α and HIF-1α play in the hypoxia pathway.

Multidisciplinary Team (MDT) Discussion Improves Overall Survival Outcomes for Metastatic Renal Cell Carcinoma Patients

Purpose

Multidisciplinary team (MDT) discussion is a widely used model to manage patients diagnosed with cancer. However, there has been no direct evidence to prove its effect on the prognosis of metastatic renal cell carcinoma (mRCC) patients, so this study explored the impact of MDT discussion on mRCC patient survival.

Methods

The clinical data of 269 mRCC patients were retrospectively collected from 2012 to 2021. The cases were grouped into the MDT and non-MDT groups, then subgroup analysis was performed according to different histology types, as well as exploring the role of MDT in patients who have undergone multiple-line therapy. Overall survival (OS) and progression free survival (PFS) were set as the study endpoint.

Results

Approximately half (48.0%, 129/269) of the patients were in the MDT group, with univariable survival analyses showing these patients had remarkably longer median OS (MDT group: 73.7 months; non-MDT group: 33.2 months, hazard ratio (HR): 0.423 (0.288, 0.622), p<0.001) and longer median PFS (MDT group: 16.9 months, non-MDT group: 12.7 months, HR: 0.722 (0.542, 0.962), p=0.026). Furthermore, MDT management resulted in longer survival for both ccRCC and non-ccRCC subgroups. Patients in the MDT group were more likely to receive multi-line therapy (MDT group: 79/129, 61.2% vs non-MDT group: 56/140, 40.0%, p<0.001), and within this patient group, MDT management still resulted in longer OS (MDT group: 94.0 months; non-MDT group: 43.5 months, p=0.009).

Conclusion

MDT is associated with prolonged overall survival in mRCC independent of histology, ensuring that patients receive better management and precise treatment.

VHL status regulates transforming growth factor-β signaling pathways in renal cell carcinoma

To evaluate the role of pVHL in the regulation of TGF-β signaling pathways in clear cell renal cell carcinoma (ccRCC) as well as in non-ccRCC; the expression of pVHL, and the TGF-β pathway components and their association with clinicopathological parameters and patient’s survival were explored. Tissue samples from 143 ccRCC and 58 non-ccRCC patients were examined by immunoblot. ccRCC cell lines were utilized for mechanistic in-vitro studies. Expression levels of pVHL were significantly lower in ccRCC compared with non-ccRCC. Non-ccRCC and ccRCC pVHL-High expressed similar levels of pVHL. Expression of the TGF-β type I receptor (ALK5) and intra-cellular domain were significantly higher in ccRCC compared with non-ccRCC. In non-ccRCC, expressions of ALK5-FL, ALK5-ICD, pSMAD2/3, and PAI-1 had no association with clinicopathological parameters and survival. In ccRCC pVHL-Low, ALK5-FL, ALK5-ICD, pSMAD2/3, and PAI-1 were significantly related with tumor stage, size, and survival. In ccRCC pVHL-High, the expression of PAI-1 was associated with stage and survival. In-vitro studies revealed that pVHL interacted with ALK5 to downregulate its expression through K48-linked poly-ubiquitination and proteasomal degradation, thus negatively controlling TGF-β induced cancer cell invasiveness. The pVHL status controls the ALK5 and can thereby regulate the TGF-β pathway, aggressiveness of tumors, and survival of the ccRCC and non-ccRCC patients.