Xuefeng Liu

Background: Sarcomatoid renal cell carcinoma (sRCC) is an aggressive RCC subtype with a poor prognosis. Although racial disparities in RCC outcomes are reported, survival patterns across racial and ethnic groups in metastatic sRCC (msRCC) remain unclear. Methods: We conducted a retrospective analysis of 2122 patients with msRCC diagnosed between 2010 and 2020 using the Surveillance, Epidemiology, and End Results (SEER) database. Patients were categorized by race and ethnicity as non-Hispanic White, non-Hispanic Black, Hispanic, Asian/Pacific Islander, or American Indian/Alaska Native. Three-year cancer-specific survival (CSS) and overall survival (OS) were estimated using Kaplan–Meier methods. Multivariable Cox proportional hazards regression models were used to evaluate racial disparities in survival. Results: Non-Hispanic Black patients experienced the poorest outcomes, with 3-year CSS and OS of 9.3% and 8.6%, compared with 23.3% and 20.9% in non-Hispanic White, 22.1% and 19.0% in Hispanic, 21.2% and 19.4% in Asian/Pacific Islander, and 23.4% and 20.7% in American Indian/Alaska Native patients. Non-Hispanic Black patients were associated with higher estimated hazards of cancer-specific mortality (HR = 1.5, p < 0.0001) and overall mortality (HR = 1.5, p < 0.0001) versus non-Hispanic White. From 2010–2015 to 2016–2020, survival improved across most racial groups with the introduction of immune checkpoint inhibitors. However, non-Hispanic Black patients remained the only group with persistently inferior survival. Subgroup analysis further demonstrated worse survival for non-Hispanic Black patients in both clear cell msRCC and non-clear cell msRCC subgroups. Conclusions: Although survival was higher during the later diagnosis period, non-Hispanic Black patients with msRCC continued to have the poorest observed survival. These differences may be associated with unmeasured social, structural, socioeconomic, healthcare access, treatment, or clinical factors, but their causes cannot be determined from this observational study. Further research is needed to identify the factors underlying these survival differences.

Human papillomavirus (HPV) is a major driver of global cancer incidence, responsible for nearly all cervical cancers and a significant proportion of oropharyngeal, anal, and other anogenital cancers. Despite the availability of effective vaccines, HPV-associated cancers persist due to persistent infection, immune evasion, and the virus’s ability to integrate into the host genome, contributing to molecular heterogeneity and therapeutic resistance. Here, we summarize molecular heterogeneity and the emerging combined therapeutic strategies. High-risk HPV types, notably HPV16 and HPV18, initiate carcinogenesis through persistent infection of epithelial basal cells and through the actions of the E6 and E7 oncoproteins, which disrupt the p53 and Rb pathways, induce telomerase activation, and promote genomic instability. A critical step in the progression to cancer is HPV genome integration, which occurs through DNA damage response pathways and results in heterogeneous insertion patterns that drive oncogene activation, tumor suppressor inactivation, and complex chromosomal rearrangements. Emerging single-cell RNA sequencing studies have highlighted the transcriptional, immune, and spatial heterogeneity of HPV-associated cancers, revealing subpopulations linked to immune escape, therapy resistance, and disease progression. These technologies have uncovered dynamic microenvironmental shifts and distinct immune cell populations, underscoring the importance of cellular and spatial heterogeneity in shaping tumor evolution and treatment response. The "hit and run" hypothesis suggests that while HPV oncoproteins are critical in early carcinogenesis, some tumors may lose dependence on viral oncogenes as they accumulate host genomic alterations, complicating detection and treatment strategies. Heterogeneity in HPV integration patterns and the tumor microenvironment contribute to variable treatment outcomes and the development of resistance to monotherapies. To overcome the challenges posed by molecular heterogeneity in HPV-associated cancers, combined therapeutic strategies targeting viral oncoproteins, host genomic vulnerabilities, and immune microenvironment are essential. Integrating single-cell transcriptomic insights with HPV integration profiles highlights how viral and host heterogeneity shape immune escape and therapeutic response, offering a framework for designing personalized combination therapies to improve outcomes in HPV-associated cancers.

Our previous study demonstrated that a Rho kinase inhibitor (Y-27632), in combination with irradiated fibroblast feeder cells, enables both normal and tumor epithelial cells from various tissues to proliferate indefinitely in vitro, without the need for exogenous viral or cellular gene transduction. These cells are referred to as Conditionally Reprogrammed Cells (CRCs). This approach has shown great promise for applications in regenerative and personalized medicine. In the present study, we first investigated whether CRCs could be genetically manipulated and stably express exogenous genes. Using lentiviral transduction of GFP, we successfully infected human foreskin keratinocytes (HFKs) cultured under CRC conditions. GFP expression was stably maintained over multiple passages and through freeze–thaw cycles. Similar stable GFP expression was also observed in CRCs derived from human tumor specimens, including neuroendocrine cervical carcinoma and prostate cancer. We next explored the use of GFP-labeled CRC-HFKs in co-culture systems with tumor-derived CRCs to evaluate colony formation and cellular heterogeneity. Our data demonstrated that CRCs from different individuals can form heterogeneous colonies, supporting the potential of CRC-based systems for modeling tissue development, regeneration, and tumor heterogeneity. To optimize the CRC platform for translational applications, we further assessed human fibroblasts and human serum as alternatives to the mouse feeder layer and bovine serum, using GFP-expressing CRCs as a functional readout. Finally, we demonstrated the capacity for gene knockdown in CRCs by successfully silencing p53 and HPV16 E6 in cervical cancer-derived CRCs using shRNA lentiviral vectors. These results collectively establish that the CRC method supports stable genetic manipulation and underscore its potential for mechanistic studies, disease modeling, and development of cell-based therapeutic strategies.

Human papillomavirus‐associated oropharyngeal squamous cell carcinoma (HPV‐OPSCC) is clinically and biologically distinct from HPV‐negative counterparts, differing in prognosis, failure patterns, and patient demographics. Although outcomes are generally favorable for HPV‐OPSCC, large randomized trials have not confirmed the safety or efficacy of treatment de‐escalation. Liquid biopsy approaches, particularly those measuring circulating tumor HPV DNA (ctHPVDNA), have emerged as promising tools for risk stratification, treatment response monitoring, and early recurrence detection. Technologies such as droplet digital PCR and next‐generation sequencing offer high sensitivity and specificity in detecting ctHPVDNA, supporting their potential utility in clinical management. Baseline ctHPVDNA levels correlate with tumor burden, HPV integration status, and clinical outcomes. Notably, rapid clearance of ctHPVDNA during radiation therapy is a strong predictor of disease control, whereas persistent or detectable ctHPVDNA after surgery is associated with a heightened risk of recurrence. For surveillance, ctHPVDNA demonstrates high positive and negative predictive values, in some studies surpassing the performance of conventional imaging modalities. Despite these encouraging findings, standardization of assay methodologies and further clinical validation are essential before ctHPVDNA can be fully incorporated into personalized treatment algorithms for HPV‐OPSCC.

The telomerase complex consists of a protein component (TERT), which has reverse transcriptase activity, and an RNA component (TERC), which serves as a template for telomere synthesis. Evidence is rapidly accumulating regarding the non-canonical functions of these components in both normal or diseased cells. An oligonucleotide-based drug, the first telomerase inhibitor, secured FDA approval in June 2024. We recently summarized the non-canonical functions of TERT in viral infections and cancer. In this review, we expand on these non-canonical functions of TERC beyond telomere maintenance. Specifically, we explore TERC’s roles in cellular aging and senescence, immune regulation, genetic diseases, human cancer, as well as involvement in viral infections and host interactions. Finally, we discuss a transcription product of telomere repeats, TERRA, and explore strategies for targeting TERC as a therapeutic approach.

Telomerase is a reverse transcriptase that adds telomeric DNA repeats at the end of chromosomes and prevents senescence, apoptosis and genome instability. The core components of TERT are a catalytic protein subunit, the telomerase reverse transcriptase (TERT), and an RNA subunit, the telomerase RNA (TR). The N-terminus of TERT has been implicated in processive DNA synthesis that is facilitated by telomere-binding domains in TERT called anchor sites. In this study, we characterized three evolutionarily conserved residues in human TERT, G145, Q169 and G172. We performed site-directed mutagenesis and created hTERT G145A, Q169A and G172A mutants. All three hTERT mutants were not able to immortalize human foreskin fibroblasts (HFFs) and maintain telomere length in cells. The G145A mutant did not abrogate hTERT enzymatic activity, while Q169 and G172 mutants exhibited severely reduced levels and enzymatic activity. When compared to wild type hTERT, the G145 mutant still could interact with telomeric DNA in cells. In contrast, substitutions of Q169 and G172 impaired the interaction between hTERT and telomeres in cells. Thus, characterization of these three conserved residue mutants in GQ motif suggested that the hTERT N-terminal DNA binding is necessary for telomerase function, but not sufficient for maintaining telomere length and immortalizing cells.

Bladder cancer (BCa) is a common urological malignancy with a high recurrence rate, often within 2 years of initial diagnosis and treatment. Due to this high recurrence, near all patients require cystoscopic surveillance, which is invasive, uncomfortable, and costly. The cost of surveillance makes this cancer the most expensive cancer per case among all cancer types in the US. Therefore, early detection of recurrence or assessment of patients’ response to treatment, particularly through non-invasive methods, is urgently needed. Since immune checkpoint inhibitors (ICIs) are widely used in many clinical trials for BCa treatment, having non-invasive and reliable biomarkers to select appropriate patients for ICI therapies or predict their treatment responses would be invaluable. Here we summarized the potential applications of programmed death-ligand 1 (PD-L1) from urine or urine BCa cell samples in BCa clinical settings. We discuss the use of both the free form of PD-L1 in urine samples and the expression levels of PD-L1 on the BCa cells shed in urine samples. Free PD-L1 can be measured with flow cytometry or ELISA-based approaches, while detecting PD-L1 on BCa cell surface requires isolating the urine-derived cancer cells and analyzing them via flow cytometry. Furthermore, we discuss the promising future research areas of urinary PD-L1 (uPD-L1) in bladder cancer, with a particular focus on the combination of conditional reprogramming cells (CRCs) technology and uPD-L1 studies, followed by an overview of several ongoing research topics. Based on current findings, uPD-L1 shows great potential as a versatile biomarker; however, further research is urgently needed to facilitate its translation into clinical applications.

HPV viral E6 and E7 onco‐proteins play a well‐known role in carcinogenesis. Host genomic alterations also play a key role in the development of HPV‐related oropharyngeal cancer and have been under‐recognized. We describe a case series of 6 metastatic/locoregionally recurrent HPVOPSCC patients with FGFR alterations. HPVOPSCC presents with distinct pattern of spread both temporally and sites of recurrence compared to non‐HPV‐related oropharyngeal cancer. Identification and reporting of genomic alterations in HPV are crucial to the understanding of disease biology and could aid in development of novel therapeutics for these patients. In addition, use of circulating tumor DNA may lead to early detection and supplement imaging in the follow up of these patients. Loco‐regional treatments may also play a key role in the management of metastatic HPV OPSCC depending on the pattern of presentation. Our case series highlights all these novelties that could lead to better treatment outcomes.