Spatially-resolved proteomics and transcriptomics: An emerging digital spatial profiling approach for tumor microenvironment

Digital spatial profiling (DSP) is an emerging powerful technology for proteomics and transcriptomics analyses in a spatially resolved manner for formalin-fixed paraffin-embedded (FFPE) samples developed by nanoString Technologies. DSP applies several advanced technologies, including high-throughput readout technologies (digital optical barcodes by nCounter instruments or next generation sequencing (NGS)), programmable digital micromirror device (DMD) technology, and microfluidic sampling technologies into traditional immunohistochemistry (IHC) and RNA in situ hybridization (ISH) approaches, creating an innovative tool for discovery, translational research, and clinical uses. Since its launch in 2019, DSP has been rapidly adopted, especially in immuno-oncology and tumor microenvironment research areas, and has revealed valuable information that was inaccessible before. In this article, we report the successful setup and validation of the first DSP technology platform in China. Both DSP spatial protein and RNA profiling approaches were validated using FFPE colorectal cancer tissues. Regions of interest (ROIs) were selected in the areas enriched with tumor cells, stroma/immune cells, or normal epithelial cells, and multiplex spatial profiling of both proteins and RNAs were performed. DSP spatial profiling data were processed and normalized accordingly, validating the high quality and consistency of the data. Unsupervised hierarchical clustering as well as principal component analysis (PCA) grouped tumor, stroma/immune cells, and normal epithelial cells into distinct clusters, indicating that the DSP approach effectively captured the spatially resolved proteomics and transcriptomics profiles of different compartments within the tumor microenvironment. In summary, the results confirmed the expected sensitivity and robustness of the DSP approach in profiling both proteins and RNAs in a spatially resolved manner. As a novel technology in highly complex spatial analyses, DSP endows refined analytical power from the tumor microenvironment perspective with the potential of scaling up to more analyzable targets at relatively low cell input levels. We expect that the DSP technology will greatly advance a wide range of biomedical research, especially in immuno-oncology and tumor microenvironment research areas.

Dosimetric comparison of intensity-modulated proton radiotherapy versus intensity-modulated photon-based radiotherapy for breast cancer

Purpose: This study aims to compare the dosimetric differences in intensity-modulated proton therapy (IMPT) using pencil beam scanning technology and intensity-modulated photon-based radiotherapy (IMRT) in hypofractionated whole-breast irradiation (HF-WBI) and find out the more beneficial technique. Methods and Materials: Eight breast cancer (BC) patients with pathological stage T1 ~ 2N0M0 were immobilized and underwent 4D-CT scanning used deep inspiration breath-hold (DIBH) technology. The IMPT and IMRT plans were designed for each patient. The IMPT plans used two en-face beam angles. IMRT plans were designed using the field in field technique. The optimization constraints of the two types of plans were identical. Prescription dose and regimen was 40.05 Gy (relative biological effect [RBE])/15 fx with a 10 Gy (RBE)/5 fx boost, five fractions a week. A dose of 95% of the target volume should not be less than the prescribed dose. The target coverage was evaluated using D1, D2, D50, D95, D98, and D99. The target dose distribution and conformity were evaluated using the Conformity index (CI) and the homogeneity index (HI). The Organs at risk (OARs) were evaluated using mean dose (Dmean) and maximum dose (Dmax). Ipsilateral Lung and Contralateral Lung were evaluated additionally using V5, V10, V20, V30. Results: The mean dose (Dmean) of the Heart (P = 0.012), Ipsilateral Lung (P = 0.036), Contralateral Lung (P = 0.012), and Spinal Cord (P = 0.012) were significantly reduced in IMPT plans. The IMPT also showed a tendency to reduce the V20 (P = 0.05) and V30 (P = 0.05) of the Ipsilateral Lung. But there was no significant difference in target coverage, homogeneity, and conformity between the IMRT and IMPT plans. Conclusion: Compared to IMRT, the IMPT using pencil beam scanning technology can spare OARs without compromising target coverage in BC patients undergoing HF-WBI, which potentially reduce the incidence of radiation-related adverse effects and thus may positively impact long-term survival.

ACE2 in tumor cells and tumor vasculature: Negligible intercellular transfer from cancer cells into endothelial cells

Cancer patients are more susceptible to severe coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Angiotensin-converting enzyme 2 (ACE2) is the functional host receptor for SARS-CoV-2 entering into human cells. Bioinformatics’ analyses have revealed that ACE2 is upregulated in some cancer cells. In the present study, we evaluated ACE2 protein expression levels in several common malignancies compared to non-cancerous normal tissues. ACE2 expression was elevated in colorectal adenocarcinoma, pancreatic adenocarcinoma, gastric adenocarcinoma, and papillary renal cell carcinoma cancer. Yet, it was suppressed in chromophobe renal cell carcinoma, testicular germ cell tumors, and papillary thyroid carcinoma. Two tumor tissue microarrays were used to evaluate the prognostic value of ACE2 expression in patients with gastric adenocarcinoma, and colorectal adenocarcinoma without COVID-19. No significant survival benefit was found for patients with overexpression of ACE2 in the tumor. In the tumor vasculature, ACE2 expression was observed in only 54% of the tumor micro-vessels. Using an in vitro co-culture of endothelial cells and tumor cells overexpressing fusion protein ACE2-red fluorescent protein, we did not observe any clear and convincing intercellular transfer of ACE2 from cancer cells into endothelial cells. In summary, alteration of ACE2 expression was found in common malignancies, but there is no evidence of intercellular transfer of ACE2 from cancer cells to endothelial cells.

The innovation and clinical application of ischemia-free organ transplantation

The incidence rate of liver cancer is increasing year by year globally. Liver transplantation has become one of the therapeutic methods for patients with liver cancer. In the past, ischemia-reperfusion injury (IRI) was unavoidable in liver transplantation, compromising recipient and graft survival. At the same time, the imbalance between the supply and demand of organs limits the use of transplantation in patients with liver cancer. Recently, advances have been made in machine perfusion techniques to reduce graft IRI. However, none of the techniques can completely abrogate graft IRI. In 2017, the concept of ischemia-free organ transplantation (IFOT) was proposed, and our group conducted the first case of ischemia-free liver transplantation (IFLT). We then extended the concept of IFOT to kidney transplantation in 2018 and to heart transplantation in 2021. Here, we review the history, strengths, and weaknesses, and the future direction of IFOT, particularly in patients with liver cancers.

Clinical advances in nasopharyngeal carcinoma surgery and a video demonstration

Nasopharyngeal carcinoma (NPC) is highly radiosensitive, and radiotherapy is recommended for newly diagnosed NPC. Because of the poor visual surgical field, narrow operating space, difficulty protecting the internal carotid artery (ICA) and poor wound healing, the development of NPC surgery has been severely limited. For recurrent NPC, some open surgical approaches, such as the maxillary swing, successfully solve the above major problems. However, these operations are traumatic and lead to many postoperative complications. With the development of minimally invasive surgery, two concepts, the “third-hand technique” and “dumpling making technique”, have been proposed, combining with the intraoperative navigation systems and multiple anatomical landmarks for identifying ICA. Endoscopic nasopharyngectomy (ENPG) can also break through the above restrictions and has become a first-line treatment for locally recurrent NPC. Moreover, a new surgical staging system for recurrent NPC was devised to aid clinicians in choosing the most suitable treatment for these patients. A current study on ENPG alone for newly diagnosed stage I NPC shows that the long-term survival outcomes after ENPG are similar to those after IMRT. ENPG was associated with low medical costs and satisfactory QOL and might be an alternative strategy for treating newly diagnosed localized stage I NPC patients who refuse radiotherapy.

Metastasis of nasopharyngeal carcinoma: What we know and do not know

Nasopharyngeal carcinoma (NPC) has the highest metastatic rate among head and neck cancers, with its underlying mechanism not yet fully unveiled. High- versus low-metastasis, NPC cell lines have been established. The footpad-popliteal lymph node metastasis model and other in vivo models have been stably used to study NPC metastasis. The histological appearance and the expression of epithelial-to-mesenchymal transition (EMT) markers might be helpful in selecting high-risk NPC patients for developing post-treatment metastasis. Tested EMT markers and their protein expression levels that correlate with patient disease-free survival in large patient cohorts include E-cadherin, N-cadherin, CD44, Twist, Snail, and Cyclin D1. Epstein-Barr virus (EBV) infection can trigger NPC metastasis from multiple angles via multiple signaling pathways. High endothelial venules are commonly seen in NPC tissues, with their role in NPC metastasis requiring clarification. The molecules that promote and inhibit NPC metastasis are introduced, with a focus on cytokines SPINK6, serglycin, interleukin 8 (IL8), Wnt family member 5A (WNT5A), and chemokine C-C motif ligand 2 (CCL2). Two videos showing NPC cells with and without SPINK6 knocked down are presented. Future directions for studying NPC metastasis are also discussed.

Foreword for Visualized Cancer Medicine: The era for dynamic visuals is here

We have seen in many circumstances of cancer research and clinical practice that the process itself is more critical and valuable than the result. For better presenting the natural movements of studied subject as well as the processes of medical intervention in treating patient, we proudly launch Visualized Cancer Medicine as a peer-reviewed publication platform covering all relevant topics in which videos play a critical role for presenting the results or the procedures. We appreciate the constant supports from our rigorous authors, dedicating editorial staff members, creative informative technology engineers, and enthusiastic readers. We hope that our small step of establishing Visualized Cancer Medicine for better scientific presentation would foster giant leaps of our understanding on cancer, which would subsequently benefit human being in many ways.