Ki67 and LSD1 Expression in Testicular Germ Cell Tumors Is Not Associated with Patient Outcome: Investigation Using a Digital Pathology Algorithm

Tissue-Based Biomarkers Important for Prognostication and Management of Genitourinary Tumors, Including Surrogate Markers of Genomic Alterations

A better understanding of the molecular alterations that underlie urologic malignancies and advances in targeted therapies has impacted classification, prognostication, and treatment. In bladder tumors, these advances include the development of antibody-drug conjugates targeting nectin-4 and Trop-2, as well as human epidermal growth factor receptor 2 and immunotherapy. In prostate cancer, assessment of the percentage of Gleason pattern 4, presence of cribriform glands, and molecular alterations, including PTEN and mismatch repair protein loss, have become standard for clinical care. In renal malignancies, alterations in TSC1/2, mammalian target of rapamycin, anaplastic lymphoma kinase, and other genes impact classification and therapeutic decisions.

Copy number amplification of FLAD1 promotes the progression of triple-negative breast cancer through lipid metabolism

Triple-negative breast cancer (TNBC) is known for frequent copy number alterations (CNAs) and metabolic reprogramming. However, the mechanism by which CNAs of metabolic genes drive distinct metabolic reprogramming and affect disease progression remains unclear. Through an integrated analysis of our TNBC multiomic dataset (n = 465) and subsequent experimental validation, we identify copy number amplification of the metabolic gene flavin-adenine dinucleotide synthetase 1 (FLAD1) as a crucial genetic event that drives TNBC progression. Mechanistically, FLAD1, but not its enzymatically inactive mutant, upregulates the enzymatic activity of FAD-dependent lysine-specific demethylase 1 (LSD1). LSD1 subsequently promotes the expression of sterol regulatory element-binding protein 1 (SREBP1) by demethylating dimethyl histone H3 lysine 9 (H3K9me2). The upregulation of SREBP1 enhances the expression of lipid biosynthesis genes, ultimately facilitating the progression of TNBC. Clinically, pharmacological inhibition of the FLAD1/LSD1/SREBP1 axis effectively suppresses FLAD1-induced tumor progression. Moreover, LSD1 inhibitor enhances the therapeutic effect of doxorubicin and sacituzumab govitecan (SG). In conclusion, our findings reveal the CNA-derived oncogenic signalling axis of FLAD1/LSD1/SREBP1 and present a promising treatment strategy for TNBC.

EHMT2/G9a and EZH2: Epimarkers in testicular germ cell tumors

BACKGROUND

Testicular germ cell tumors remain the most frequent solid malignancies in young males. Despite excellent prognosis, the fact that only 60% of patients at diagnosis have elevated serum tumor markers (dependent on stage and histology) and the poor quality of life of patients who develop resistance to chemotherapy cannot be neglected. Consequently, it is mandatory to bring out novel biomarkers.

OBJECTIVES

The main goal was to evaluate EZH2 and EHMT2/G9a immunoexpression in a well-characterized patients' cohort of primary and metastatic testicular germ cell tumors, seeking associations with clinicopathological features and discovering differential immunoexpression patterns among specific subtypes.

MATERIALS AND METHODS

First, an in silico analysis of the Cancer Genome Atlas database was performed regarding EZH2 and EHMT2/G9a. Then, immunohistochemistry for EZH2 and EHMT2/G9a was carried out in a cohort of testicular germ cell tumor patients, comprising 155 chemo-naïve primary tumors and 11 chemo-treated metastases. Immunoexpression was evaluated using a digital pathology analysis software.

RESULTS

Higher EZH2 and EHMT2/G9a expression levels were found in non-seminoma in the in silico analysis, particularly in embryonal carcinoma. Through digital pathology analysis, non-seminomas showed significantly higher EZH2 and EHMT2/G9a immunoexpression, with embryonal carcinoma showing higher expression. Moreover, mixed tumors with 50% or more of embryonal carcinoma component revealed the highest nuclei positivity for both biomarkers. Cisplatin-exposed metastases demonstrated a higher EZH2-positive nuclei and H-score, as well as higher EHMT2/G9a-positive nuclei.

DISCUSSION AND CONCLUSION

Overall, our data suggest that EZH2 and EHMT2/G9a might be associated with greater aggressiveness and, eventually, involved in the metastatic setting, paving the way for testing targeted therapies.

H3 histone methylation landscape in male urogenital cancers: from molecular mechanisms to epigenetic biomarkers and therapeutic targets

During the last decades, male urogenital cancers (including prostate, renal, bladder and testicular cancers) have become one of the most frequently encountered malignancies affecting all ages. While their great variety has promoted the development of various diagnosis, treatment and monitoring strategies, some aspects such as the common involvement of epigenetic mechanisms are still not elucidated. Epigenetic processes have come into the spotlight in the past years as important players in the initiation and progression of tumors, leading to a plethora of studies highlighting their potential as biomarkers for diagnosis, staging, prognosis, and even as therapeutic targets. Thus, fostering research on the various epigenetic mechanisms and their roles in cancer remains a priority for the scientific community. This review focuses on one of the main epigenetic mechanisms, namely, the methylation of the histone H3 at various sites and its involvement in male urogenital cancers. This histone modification presents a great interest due to its modulatory effect on gene expression, leading either to activation (e.g., H3K4me3, H3K36me3) or repression (e.g., H3K27me3, H3K9me3). In the last few years, growing evidence has demonstrated the aberrant expression of enzymes that methylate/demethylate histone H3 in cancer and inflammatory diseases, that might contribute to the initiation and progression of such disorders. We highlight how these particular epigenetic modifications are emerging as potential diagnostic and prognostic biomarkers or targets for the treatment of urogenital cancers.

An update on diagnostic tissue-based biomarkers in testicular tumors

Testicular cancer is rare overall but comprises the most common solid malignancy diagnosed in young men aged ∼20-40 years. Most testicular neoplasms generally fall into 2 broad categories: germ cell tumors (GCTs; ∼95%) and sex cord-stromal tumors (SCSTs ∼5%). Given the relative rarity of these tumors, diagnostic biomarkers are highly relevant for their diagnosis. Over the past several decades, diagnostic biomarkers have improved dramatically through targeted immunohistochemical and molecular characterization. Despite these recent advances, most markers are not perfectly sensitive or entirely specific. Therefore, they need to be used in combination and interpreted in context. In this review, we summarize tissue-based biomarkers relevant to the pathologist, with a focus on practical diagnostic issues that relate to testicular GCT and SCST.