Combined with interventional therapy, immunotherapy can create a new outlook for tumor treatment

Immune checkpoint inhibitors in cholangiocarcinoma

Cholangiocarcinoma is an epithelial malignancy originating in the biliary tracts and frequently recurs even with surgical resection. Unresectable disease has a 5-year overall survival of less than 10%. Given this poor prognosis, additional therapies are urgently needed. Chemotherapy has been the mainstay of treatment for many years. However, with the incorporation of immunotherapy into the treatment of other malignancies, there has been a great deal of interest in immunotherapy for biliary cancers. Recently, durvalumab was approved in combination with gemcitabine and cisplatin for the treatment of unresectable cholangiocarcinoma in the first-line setting. However, predicting which patients may respond to immunotherapy remains a challenge due to the lack of a reliable biomarker.

Immuno-PET imaging of PD-L1 expression in patient-derived lung cancer xenografts with [68Ga]Ga-NOTA-Nb109

Background

Accurate evaluation of programmed death-ligand 1 (PD-L1) expression levels in cancer patients may be useful in the identification of potential candidates for anti-programmed death-1/PD-L1 (anti-PD-1/PD-L1) immune checkpoint therapy to improve the response rate of immune checkpoint blockade therapy. This study evaluated the feasibility of the nanobody-based positron emission tomography (PET) tracer [68Ga]Ga-NOTA-Nb109 for immuno-PET imaging of PD-L1 in lung cancer patient-derived xenograft (PDX).

Methods

We constructed 2 PDXs of lung adenocarcinoma (ADC) and lung squamous cell carcinoma (SCC) and used them for immuno-PET imaging. A 2-hour dynamic PET scanning was performed on the samples and the in vivo biodistribution and metabolism of [68Ga]Ga-NOTA-Nb109 were investigated using region of interest (ROI) analysis. The ex vivo biodistribution of [68Ga]Ga-NOTA-Nb109 in the 2 PDXs was investigated by static PET scanning. In addition, tumor PD-L1 expression in the 2 PDXs was evaluated by autoradiography, western blot, and immunohistochemical (IHC) analysis.

Results

Noninvasive PET imaging showed that [68Ga]Ga-NOTA-Nb109 can accurately and sensitively assess the PD-L1 expression in non-small cell lung cancer (NSCLC) PDX models. The maximum [68Ga]Ga-NOTA-Nb109 uptake by the ADC PDX LU6424 and the SCC PDX LU6437 were 3.13%±0.35% and 2.60%±0.32% injected dose per milliliter of tissue volume (ID/mL), respectively, at 20 min post injection. In vivo and ex vivo biodistribution analysis showed that [68Ga]Ga-NOTA-Nb109 was rapidly cleared through renal excretion and an enhanced signal-to-noise ratio (SNR) was achieved. Ex vivo PD-L1 expression analysis showed good agreement with in vivo PET imaging results.

Conclusions

This study demonstrated that [68Ga]Ga-NOTA-Nb109 could be applied with PET imaging to noninvasively and accurately monitor PD-L1 expression in vivo for screening patients who may be responsive to immunotherapy and to guide the development of appropriate treatment strategies for such patients.

Associations between tumor grade, contrast-enhanced ultrasound features, and microvascular density in patients with clear cell renal cell carcinoma: a retrospective study

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) comprises 70% of all renal cell carcinomas (RCCs). Currently, the most important prognostic factor for this type of carcinoma is the World Health Organization/International Society of Urological Pathology (WHO/ISUP) grade. However, nonsurgical methods are rarely used to determine a tumor's WHO/ISUP grade, thus limiting the development of nonsurgical therapies. Due to variations in microvascular density (MVD) at different stages of tumor growth, contrast-enhanced ultrasound (CEUS) features may provide a noninvasive method for evaluating the WHO/ISUP grade of ccRCC.

METHODS

In this study, we analyzed confirmed cases of ccRCC using CEUS features. We also used CD34 and CD31 antibodies to determine MVD. The heterogeneity of CD34 and CD31 expressions were used to determine different degrees of angiogenesis.

RESULTS

When compared to WHO/ISUP grade I/II (G1/G2) tumors, grade III/IV (G3/G4) tumors had reduced peak intensity (PI) (P=0.006), time to peak (TTP) (P<0.001), and relative enhancement percentage index (∆PI%) (P<0.001). However, the frequency of incomplete pseudocapsule (P=0.049) and slow wash-in (P=0.001) was significantly higher in G3/G4 tumors. A cut-off value of ∆PI% <33.15% (P<0.001) allowed identification of G3/G4 tumors with an area under the curve (AUC) of 0.80 [95% confidence interval (CI): 0.70 to 0.91) and a sensitivity of 80%. The mean CD34+ MVD (P<0.001) and CD31+ MVD (P<0.001) were significantly lower in G3/G4 tumors. A positive correlation was revealed between ∆PI% and MVD. There was a statistically significant difference in the density of undifferentiated vessels between the slow wash-in and fast wash-in cases (P<0.001).

CONCLUSIONS

The features of CEUS are effective for differentiating G3/G4 tumors from G1/G2. There was a positive correlation detected between ∆PI% and MVD, and the density of undifferentiated vessels showed a significant difference between slow wash-in and fast wash-in cases. These findings indicate that CEUS can enable the sonographic visualization of tumor angiogenesis and thus be considered an acceptable method for the nonsurgical assessment of tumor microvascular distribution and grade.