p16(INK4A)-deficiency predicts response to combined HER2 and CDK4/6 inhibition in HER2+ breast cancer brain metastases

Meningioma: Novel Diagnostic and Therapeutic Approaches

Background/Objectives: Meningiomas are the most common intracranial tumors. Surgery and radiation therapy are the cornerstones of treatment and no standard of care therapy exists for refractory meningiomas. This manuscript aims to provide a comprehensive review of novel diagnostic and therapeutic approaches against these tumors. Methods: A search for the existing literature on systemic therapies for meningiomas was performed on PubMed and a search for presently accruing clinical trials was performed on ClinicalTrials.gov. Results: Systemic treatments, including chemotherapy, somatostatin analogs, anti-hormone therapy, and anti-angiogenic therapy, have been extensively studied with marginal success. Targeted therapies are actively being studied for the treatment of meningiomas, including focal adhesion kinase (FAK), sonic hedgehog signaling pathway, phosphoinositide-3-kinase (PI3K), and cyclin-dependent kinases (CDK) inhibitors. These driver mutations are present only in a subset of meningiomas. In stark contrast, somatostatin receptor 2 (SSTR2) is ubiquitously expressed in meningiomas and was formerly targeted with somatostatin analogs with modest success. Theranostic SSTR2-targeting via [68Ga]DOTATATE for PET imaging and β-emitting [177Lu]DOTATATE for the treatment of meningiomas are currently under active investigation. Conclusions: A nuanced approach is needed for the treatment of refractory meningiomas. Targeted therapies show promise.

Lipid metabolic reprograming: the unsung hero in breast cancer progression and tumor microenvironment

Aberrant lipid metabolism is a well-recognized hallmark of cancer. Notably, breast cancer (BC) arises from a lipid-rich microenvironment and depends significantly on lipid metabolic reprogramming to fulfill its developmental requirements. In this review, we revisit the pivotal role of lipid metabolism in BC, underscoring its impact on the progression and tumor microenvironment. Firstly, we delineate the overall landscape of lipid metabolism in BC, highlighting its roles in tumor progression and patient prognosis. Given that lipids can also act as signaling molecules, we next describe the lipid signaling exchanges between BC cells and other cellular components in the tumor microenvironment. Additionally, we summarize the therapeutic potential of targeting lipid metabolism from the aspects of lipid metabolism processes, lipid-related transcription factors and immunotherapy in BC. Finally, we discuss the possibilities and problems associated with clinical applications of lipid‑targeted therapy in BC, and propose new research directions with advances in spatiotemporal multi-omics.

Breakage fusion bridge cycles drive high oncogene number with moderate intratumoural heterogeneity

Oncogene amplification is a key driver of cancer pathogenesis. Both breakage fusion bridge (BFB) cycles and extrachromosomal DNA (ecDNA) can lead to high oncogene copy numbers, but the impact of BFB amplifications on intratumoral heterogeneity, treatment response, and patient survival remains poorly understood due to detection challenges with DNA sequencing. We introduce an algorithm, OM2BFB, designed to detect and reconstruct BFB amplifications using optical genome mapping (OGM). OM2BFB demonstrates high precision (>93%) and recall (92%) in identifying BFB amplifications across cancer cell lines, patient-derived xenograft models, and primary tumors. Comparisons using OGM reveal that BFB detection with our AmpliconSuite toolkit for short-read sequencing also achieves high precision, though with reduced sensitivity. We identify 371 BFB events through whole genome sequencing of 2557 primary tumors and cancer cell lines. BFB amplifications are prevalent in cervical, head and neck, lung, and esophageal cancers, but rare in brain cancers. Genes amplified through BFB exhibit lower expression variance, with limited potential for regulatory adaptation compared to ecDNA-amplified genes. Tumors with BFB amplifications (BFB(+)) show reduced structural heterogeneity in amplicons and delayed resistance onset relative to ecDNA(+) tumors. These findings highlight ecDNA and BFB amplifications as distinct oncogene amplification mechanisms with differing biological characteristics, suggesting distinct avenues for therapeutic intervention.

Potentially actionable molecular alterations in particular related to poor oncologic outcomes in salivary gland carcinomas

AIM

The study was designed to evaluate molecular alterations, relevant to the prognosis and personalized therapy of salivary gland cancers (SGCs).

MATERIALS AND METHODS

DNA was extracted from archival tissue of 40 patients with various SGCs subtypes. A targeted next-generation sequencing (NGS) panel was used for the identification of small-scale mutations, focal and chromosomal arm-level copy number changes. The final analysis included selected genes with potential actionable aberrations for targeted therapies and outcome predictions in 37 tumours' samples.

RESULTS

The follow-up of the SGCs study cohort revealed disease recurrence or metastasis in 19 patients and indicated poor individual outcomes. The mean disease-free survival (DFS) within the poor outcome group was 2.4 years, and the overall survival (OS) was 5.4 years. The DFS and OS of the remaining 18 patients with favourable outcomes were 8.3 years. The genes most frequently affected with aberrations were NF1 (n = 9, 24%) and TP53 (n = 8, 22%), with increased occurrence observed in the poor outcome group: NF1 (n = 6, 32%) and TP53 (n = 6, 32%). CDKN2A biallelic deletion was the most common copy number variation (n = 5), and was detected in 4 cases with identified disease relapse. TERT promoter mutation and amplification were found in myoepithelial carcinoma. A p.Ile35Thr mutation was discovered in CTNNB1 in two cases of adenoid cystic carcinoma. ERBB2 alterations were remarkable for SDC ex PA. Furthermore, TP53 mutation was established as a relevant negative prognostic factor for overall survival (p = 0,04). The analysis revealed potentially actionable genes in detected alterations in: MECA 100% (1/1), SDC 100% (7/7), AD 92% (11/12), Ca ex PA 82% (18/22), MECA 65% (20/31), AdCC 64% (9/14) and AcCC 0% (0/1).

CONCLUSIONS

SGCs are a heterogeneous group of malignancies with distinct molecular landscape that characterized by poor prognosis and inadequate treatment options. Nonstandard strategies might be beneficial for patients who suffer from salivary gland cancers. Wider utilization of NGS analysis may increase the opportunity for patients with those rare cancers to receive more precise, personalized therapy.

Cancer takes many paths through G1/S

In the commonly accepted paradigm for control of the mammalian cell cycle, sequential cyclin-dependent kinase (CDK) and cyclin activities drive the orderly transition from G1 to S phase. However, recent studies using different technological approaches and examining a broad range of cancer cell types are challenging this established paradigm. An alternative model is evolving in which cell cycles utilize different drivers and take different trajectories through the G1/S transition. We are discovering that cancer cells in particular can adapt their drivers and trajectories, which has important implications for antiproliferative therapies. These studies have helped to refine an understanding of how CDK inhibition impinges on proliferation and have significance for understanding fundamental features of cell biology and cancer.

Effectiveness and Safety of Pyrotinib-Based Therapy in the Treatment of HER2-Positive Breast Cancer Patients with Brain Metastases: A Multicenter Real-World Study

BACKGROUND

Approximately 30% to 50% of patients with human epidermal growth factor receptor 2-positive metastatic breast cancer develop brain metastasis (BMs). Pyrotinib has shown promising efficacy in these patients. However, real-world evidence supporting its use is scarce. Therefore, we evaluate the efficacy and safety of pyrotinib-based regimens in the real world.

MATERIALS AND METHODS

We enrolled patients with BMs from various healthcare facilities in China's Shandong region and used an updated breast-graded prognostic assessment (breast-GPA) to predict survival outcomes.

RESULTS

Efficacy and toxicity were assessed in 101 patients. Overall, the median progression-free survival (PFS) was 11.0 months (95% CI, 7.6-14.4 months). PFS was shorter in patients with a breast-GPA of 0 to 2.0 (P< .001). Previous treatment with pertuzumab plus trastuzumab (P = .039) and varying numbers of BMs (P = .028) had a significant positive correlation with PFS. Additionally, radiotherapy (P = .033) for BMs, especially pyrotinib concurrent with radiotherapy (P = .013), significantly prolonged the PFS. In patients with a breast-GPA of 0 to 2.0, a significant difference in PFS was observed depending on whether the brain was the first metastatic site (P< .001). Furthermore, a breast-GPA (0-2.0 vs. 2.5-4.0), and radiotherapy for BMs were found to be independent predictors of PFS. Overall, the objective response rate was 42.6%, while the disease control rate was 88.1%. Diarrhea emerged as the most common adverse event.

CONCLUSION

Pyrotinib-based therapy is effective and tolerable in human epidermal growth factor receptor 2-positive metastatic breast cancer with BMs. Patients who underwent radiotherapy for BMs, particularly those who received pyrotinib concurrently with radiotherapy, exhibited a more favorable prognosis.

Pyrotinib and trastuzumab plus palbociclib and fulvestrant in HR+/HER2+ breast cancer patients with brain metastasis

Human epidermal growth factor receptor 2-positive (HER2+) breast cancer (BC) patients are at a high risk of developing metastases in the brain. However, research focusing on treatment strategies for hormonal receptor positive (HR+), HER2+ BC patients with brain metastases (BM) remains limited. Thus, a multi-center, prospective trial was conducted in China. Women over the age of 18 who were naive to whole brain radiotherapy and had estrogen receptor (ER)/progesterone-receptor (PgR) positive, HER2+ BM were treated with palbociclib, fulvestrant, trastuzumab and pyrotinib, until disease progression or the development of intolerable side effects. The primary endpoint was objective response rate (ORR) in the central nervous system (CNS). This ongoing study is still recruiting participants and is registered with ClinicalTrials.gov (NCT04334330). This report presents the findings from an interim analysis. From December 4, 2020, to November 2, 2022, 15 patients were enrolled. Among the 14 patients who were evaluable for clinical response, the ORR was 35.7% (95% CI: 12.8-64.9%), with a CNS-ORR of 28.6% (95% CI: 8.4-58.1%). The median follow-up period was 6.3 months (range, 2.1-14.3 months), during which the median progression-free survival (PFS) was 10.6 months (95% CI: 4.3-16.9 months), and the median time to CNS progression was 8.5 months (95% CI: 5.9-11.1 months). The most common adverse event was diarrhea (93%), with 33% having grade 3 and 6.7% having grade 4. The study suggests that the combination of palbociclib, trastuzumab, pyrotinib and fulvestrant offers a promising chemo-free treatment strategy for HR+, HER2+ BC patients with BM.

Clinical considerations of CDK4/6 inhibitors in HER2 positive breast cancer

Deregulation of cell cycles can result in a variety of cancers, including breast cancer (BC). In fact, abnormal regulation of cell cycle pathways is often observed in breast cancer, leading to malignant cell proliferation. CDK4/6 inhibitors (CDK4/6i) can block the G1 cell cycle through the cyclin D-cyclin dependent kinase 4/6-inhibitor of CDK4-retinoblastoma (cyclinD-CDK4/6-INK4-RB) pathway, thus blocking the proliferation of invasive cells, showing great therapeutic potential to inhibit the spread of BC. So far, three FDA-approved drugs have been shown to be effective in the management of advanced hormone receptor positive (HR+) BC: palbociclib, abemaciclib, and ribociclib. The combination strategy of CDK4/6i and endocrine therapy (ET) has become the standard therapeutic regimen and is increasingly applied to advanced BC patients. The present study aims to clarify whether CDK4/6i can also achieve a certain therapeutic effect on Human epidermal growth factor receptor 2 positive (HER2+) BC. Studies of CDK4/6i are not limited to patients with estrogen receptor positive/human epidermal growth factor receptor 2 negative (ER+/HER2-) advanced BC, but have also expanded to other types of BC. Several pre-clinical and clinical trials have demonstrated the potential of CDK4/6i in treating HER2+ BC. Therefore, this review summarizes the current knowledge and recent findings on the use of CDK4/6i in this type of BC, and provides ideas for the discovery of new treatment modalities.

Breakage fusion bridge cycles drive high oncogene copy number, but not intratumoral genetic heterogeneity or rapid cancer genome change

Oncogene amplification is a major driver of cancer pathogenesis. Breakage fusion bridge (BFB) cycles, like extrachromosomal DNA (ecDNA), can lead to high copy numbers of oncogenes, but their impact on intratumoral heterogeneity, treatment response, and patient survival are not well understood due to difficulty in detecting them by DNA sequencing. We describe a novel algorithm that detects and reconstructs BFB amplifications using optical genome maps (OGMs), called OM2BFB. OM2BFB showed high precision (>93%) and recall (92%) in detecting BFB amplifications in cancer cell lines, PDX models and primary tumors. OM-based comparisons demonstrated that short-read BFB detection using our AmpliconSuite (AS) toolkit also achieved high precision, albeit with reduced sensitivity. We detected 371 BFB events using whole genome sequences from 2,557 primary tumors and cancer lines. BFB amplifications were preferentially found in cervical, head and neck, lung, and esophageal cancers, but rarely in brain cancers. BFB amplified genes show lower variance of gene expression, with fewer options for regulatory rewiring relative to ecDNA amplified genes. BFB positive (BFB (+)) tumors showed reduced heterogeneity of amplicon structures, and delayed onset of resistance, relative to ecDNA(+) tumors. EcDNA and BFB amplifications represent contrasting mechanisms to increase the copy numbers of oncogene with markedly different characteristics that suggest different routes for intervention.

Dalpiciclib and pyrotinib in women with HER2-positive advanced breast cancer: a single-arm phase II trial

CDK4/6 inhibitors have shown a synergistic effect with anti-HER2 therapy in hormone receptor (HR)-positive and HER2-positive breast cancer (BC). In this phase 2 study (NCT04293276), we aim to evaluate a dual-oral regimen of CDK4/6 inhibitor dalpiciclib combined with HER2 tyrosine kinase inhibitor pyrotinib as front-line treatment in women with HER2-positive advanced BC (n = 41) including those with HR-negative disease. The primary endpoint is the objective response rate, and secondary endpoints include progression-free survival (PFS), overall survival (OS), and safety. With a median follow-up of 25.9 months, 70% (28/40) of assessable patients have a confirmed objective response, meeting the primary endpoint. The median PFS is 11.0 months (95% CI = 7.3-19.3), and OS data are not mature. The most common grade 3 or 4 treatment-related adverse events (AEs) are decreased white blood cell count (68.3%), decreased neutrophil count (65.9%), and diarrhea (22.0%). Most AEs are manageable, and no treatment-related deaths occur. These findings suggest that this combination may have promising activity and manageable toxicity. Further investigation is needed.

Molecular signaling network and therapeutic developments in breast cancer brain metastasis

Breast cancer (BC) is one of the most frequently diagnosed cancers in women worldwide. It has surpassed lung cancer as the leading cause of cancer-related death. Breast cancer brain metastasis (BCBM) is becoming a major clinical concern that is commonly associated with ER-ve and HER2+ve subtypes of BC patients. Metastatic lesions in the brain originate when the cancer cells detach from a primary breast tumor and establish metastatic lesions and infiltrate near and distant organs via systemic blood circulation by traversing the BBB. The colonization of BC cells in the brain involves a complex interplay in the tumor microenvironment (TME), metastatic cells, and brain cells like endothelial cells, microglia, and astrocytes. BCBM is a significant cause of morbidity and mortality and presents a challenge to developing successful cancer therapy. In this review, we discuss the molecular mechanism of BCBM and novel therapeutic strategies for patients with brain metastatic BC.

P16 Expression in Human Breast Carcinoma and its Relationship to Clinicopathological Parameters

Background

p16 is a cyclin-dependent kinase inhibitor and a cardinal regulator of the cell cycle. The relationship between p16 overexpression and poor prognosis of breast cancer has been reported in some studies. This study aimed to evaluate p16 expression in breast cancer in comparison to normal breast tissue and determine the association between p16 expression and clinicopathological parameters in breast cancer.

Materials and Methods

Paraffin blocks of 110 samples were studied. These included 40 invasive breast carcinoma (tumor group) and normal tissue adjacent to the tumor (tumor control), as well as 30 normal mammoplasty specimens (normal control). Samples were from the pathology archive of Alzahra Hospital, Isfahan, Iran, from 2016 to 2020. p16 expression was studied and compared in these three groups using the immunohistochemistry technique. Moreover, the relationship between p16 expression and age, tumor size, carcinoma subtype, tumor grade, and lymph node involvement was investigated in the tumor group. SPSS version 16 was used to analyze data.

Results

p16 expression showed a significant difference between the tumor group and the two control groups with a significantly higher expression in the tumor group. There was a significant direct relationship between the intensity of p16 expression and the number of involved lymph nodes (P < 0.001). No significant relationship was detected between p16 expression and other clinicopathological factors.

Conclusion

p16 seems to have a rather significant expression in breast cancer in comparison to normal breast parenchyma. However, among clinicopathological parameters, we found only a direct relationship between lymph node involvement and intensity of p16 expression.

Identification and validation of the cellular senescence-related molecular subtypes of triple negative breast cancer via integrating bulk and single-cell RNA sequencing data

Patients with triple-negative breast cancer (TNBC) reportedly benefit from immune checkpoint blockade (ICB) therapy. However, the subtype-specific vulnerabilities of ICB in TNBC remain unclear. As the complex interplay between cellular senescence and anti-tumor immunity has been previously discussed, we aimed to identify markers related to cellular senescence that may serve as potential predictors of response to ICB in TNBC. We used three transcriptomic datasets derived from ICB-treated breast cancer samples at both scRNA-seq and bulk-RNA-seq levels to define the subtype-specific vulnerabilities of ICB in TNBC. Differences in the molecular features and immune cell infiltration among the different TNBC subtypes were further explored using two scRNA-seq, three bulk-RNA-seq, and two proteomic datasets. 18 TNBC samples were collected and utilized to verify the association between gene expression and immune cell infiltration by multiplex immunohistochemistry (mIHC). A specific type of cellular senescence was found to be significantly associated with response to ICB in TNBC. We employed the expression of four senescence-related genes, namely CDKN2A, CXCL10, CCND1, and IGF1R, to define a distinct senescence-related classifier using the non-negative matrix factorization approach. Two clusters were identified, namely the senescence-enriching cluster (C1; CDKN2A high CXCL10 high CCND1 low IGF1R low) and proliferating-enriching cluster (C2; CDKN2A low CXCL10 low CCND1 high IGF1R high). Our results indicated that the C1 cluster responds better to ICB and behaves with higher CD8+ T cell infiltration than the C2 cluster. Altogether, in this study, we developed a robust cellular senescence-related classifier of TNBC based on the expression of CDKN2A, CXCL10, CCND1, and IGF1R. This classifier act as a potential predictor of clinical outcomes and response to ICB.

Preclinical and Clinical Efficacy of Trastuzumab Deruxtecan in Breast Cancer Brain Metastases

PURPOSE

Brain metastases can occur in up to 50% of patients with metastatic HER2-positive breast cancer. Because patients with active brain metastases were excluded from previous pivotal clinical trials, the central nervous system (CNS) activity of the antibody-drug conjugate trastuzumab deruxtecan (T-DXd) is not well characterized.

EXPERIMENTAL DESIGN

We studied how T-DXd affects growth and overall survival in orthotopic patient-derived xenografts (PDX) of HER2-positive and HER2-low breast cancer brain metastases (BCBM). Separately, we evaluated the effects of T-DXd in a retrospective cohort study of 17 patients with stable or active brain metastases.

RESULTS

T-DXd inhibited tumor growth and prolonged survival in orthotopic PDX models of HER2-positive (IHC 3+) and HER2-low (IHC 2+/FISH ratio < 2) BCBMs. T-DXd reduced tumor size and prolonged survival in a T-DM1-resistant HER2-positive BCBM PDX model. In a retrospective multi-institutional cohort study of 17 patients with predominantly HER2-positive BCBMs, the CNS objective response rate (ORR) was 73% (11/15) while extracranial response rate was 45% (5/11). In the subset of patients with untreated or progressive BCBM at baseline, the CNS ORR was 70% (7/10). The median time on treatment with T-DXd was 8.9 (1.3-16.2) months, with 42% (7/17) remaining on treatment at data cutoff.

CONCLUSIONS

T-DXd demonstrates evidence of CNS activity in HER2-positive and HER2-low PDX models of BCBM and preliminary evidence of clinical efficacy in a multi-institution case series of patients with BCBM. Prospective clinical trials to further evaluate CNS activity of T-DXd in patients with active brain metastases are warranted. See related commentary by Soffietti and Pellerino, p. 8.

Therapeutic Strategies for Targeting CDKN2A Loss in Melanoma

Loss of the tumor suppressor gene CDKN2A, encoding p16 and p14, is a frequent event driving melanoma progression. Therefore, therapeutic strategies aimed at CDKN2A loss hold great potential to improve melanoma treatment. Pharmacological inhibition of the p16 targets CDK4/6 is a prime example of such a strategy. Other approaches exploit cell cycle deregulation, target metabolic rewiring, epigenetically restore expression, act on dependencies resulting from co-deleted genes, or are directed at the effects of CDKN2A loss on immune responses. This review explores these therapeutic strategies targeting CDKN2A loss, which potentially open up new avenues for precision medicine in melanoma.