Survival of patients with metastatic leiomyosarcoma: the MD Anderson Clinical Center for targeted therapy experience

Molecular Heterogeneity in Leiomyosarcoma and Implications for Personalised Medicine

OPINION STATEMENT

Leiomyosarcoma (LMS) is one of the more common subtypes of soft tissue sarcomas (STS), accounting for about 20% of cases. Differences in anatomical location, risk of recurrence and histomorphological variants contribute to the substantial clinical heterogeneity in survival outcomes and therapy responses observed in patients. There is therefore a need to move away from the current one-size-fits-all treatment approach towards a personalised strategy tailored for individual patients. Over the past decade, tissue profiling studies have revealed key genomic features and an additional layer of molecular heterogeneity among patients, with potential utility for optimal risk stratification and biomarker-matched therapies. Furthermore, recent studies investigating intratumour heterogeneity and tumour evolution patterns in LMS suggest some key features that may need to be taken into consideration when designing treatment strategies and clinical trials. Moving forward, national and international collaborative efforts to aggregate expertise, data, resources and tools are needed to achieve a step change in improving patient survival outcomes in this disease of unmet need.

Case report: Highly response to low-dose brachytherapy in recurrent retroperitoneal leiomyosarcoma with FANCD2 frameshift mutation: a unique case study

We report a case of recurrent retroperitoneal leiomyosarcoma in a male who achieved a rapid and robust but transient clinical response to low-dose iodine-125 brachytherapy. A FANCD2 frameshift mutation was detected by gene sequencing in the cancerous tissue.

PD-1 Inhibition in metastatic high tumour mutational burden (TMB) leiomyosarcoma with clinicopathological correlates

Leiomyosarcoma (LMS) is a subtype of sarcoma derived from smooth muscle cells. Unfortunately, this malignancy has a high rate of metastatic disease. Palliative systemic therapy has historically relied on cytotoxic agents such as doxorubicin, which have low rates of response. Immunotherapy has not been shown to be effective for most patients with sarcoma, including those with LMS. However, this has not been well described for patients with LMS and high tumour mutational burden (TMB). Herein, we report the case of a woman in her late 50s with metastatic high TMB (>10) leiomyosarcoma treated with pembrolizumab.

Novel metabolomics-biohumoral biomarkers model for predicting survival of metastatic soft-tissue sarcomas

Soft tissue sarcomas (STSs) are rare malignant tumors that are difficult to prognosticate using currently available instruments. Omics sciences could provide more accurate and individualized survival predictions for patients with metastatic STS. In this pilot, hypothesis-generating study, we integrated clinicopathological variables with proton nuclear magnetic resonance (1H NMR) plasma metabolomic and lipoproteomic profiles, capturing both tumor and host characteristics, to identify novel prognostic biomarkers of 2-year survival. Forty-five metastatic STS (mSTS) patients with prevalent leiomyosarcoma and liposarcoma histotypes receiving trabectedin treatment were enrolled. A score combining acetate, triglycerides low-density lipoprotein (LDL)-2, and red blood cell count was developed, and it predicts 2-year survival with optimal results in the present cohort (84.4% sensitivity, 84.6% specificity). This score is statistically significant and independent of other prognostic factors such as age, sex, tumor grading, tumor histotype, frailty status, and therapy administered. A nomogram based on these 3 biomarkers has been developed to inform the clinical use of the present findings.

B-cell lymphoma 2 family members and sarcomas: a promising target in a heterogeneous disease

Targeting the B-cell lymphoma 2 (Bcl-2) family proteins has been the backbone for hematological malignancies with overall survival improvements. The Bcl-2 family is a major player in apoptosis regulation and, has captured the researcher's interest in the treatment of solid tumors. Sarcomas are a heterogeneous group of diseases, comprising several entities, with high morbidity and mortality and with few specific therapies available. The treatment for sarcomas is based on platinum regimens, with variable results and poor outcomes, especially in advanced lesions. The high number of different sarcoma entities makes treatment standardization as well as the performance of clinical trials difficult. The use of Bcl-2 family members modifiers has revealed promising results in in vitro and in vivo models and may be a valid option, especially when used in combination with chemotherapy. In this article, a revision of these results and possibilities for the use of Bcl-2 family members inhibitors in sarcomas was performed.

Not All Leiomyosarcomas Are the Same: How to Best Classify LMS

OPINION STATEMENT

Leiomyosarcoma arises from smooth muscle and represents one of the most common soft tissue sarcomas. Despite aggressive multimodality care, over half of the patients will ultimately develop metastatic and incurable disease with a median survival of 12-18 months. At present, there is no standard system to classify leiomyosarcoma, which itself is a heterogeneous disease. Classification by tumor location is the most simplistic approach and is most frequently utilized in clinical practice. Tumor location impacts diagnosis (recognition pre-operatively versus at the time of surgery) as well as treatment (ability to completely resect with clear margins with minimal morbidity). While tumor location can impact prognosis, for example, extremity tumors would generally be considered as lower risk than inferior vena cava tumors, leiomyosarcoma can exhibit a heterogeneous behavior irrespective of tumor location. Specifically, some patients have rapidly progressing disease despite aggressive chemotherapy, while others display a more indolent course even in the metastatic setting. The pathogenic drivers of the heterogeneity observed in tumor behavior are not well understood. As we learn more about the molecular composition of leiomyosarcoma, various classification groups have been proposed as discussed here. Ultimately, it is unlikely that one variable will be adequate for tumor classification, and a combination of location and molecular composition will be necessary to develop appropriate risk stratification nomograms and treatment strategies.

HPV51-associated Leiomyosarcoma: A Novel Class of TP53/RB1-Wildtype Tumor With Predilection for the Female Lower Reproductive Tract

Inactivating mutations in tumor suppressor genes TP53 and RB1 are considered central drivers in leiomyosarcomas (LMSs). In high-risk human papillomavirus (HPV)-related tumors, a similar functional outcome is achieved through oncoproteins E6 and E7, which inactivate the p53 and RB1 proteins, respectively. Here, we hypothesized that HPV infection could provide an alternative mechanism for tumorigenesis in a subset of TP53/RB1-wildtype LMS. We evaluated tumor samples from 2585 consecutive unique patients carrying a diagnosis of gynecologic or soft tissue LMS. Tumor DNA and available RNA were analyzed by hybrid-capture-based next-generation sequencing/comprehensive genomic profiling of 406 genes and transcripts (FoundationOneHeme). Of the initial 2585 cases, we excluded 16 based on the presence of molecular alterations that are considered defining for sarcomas other than LMS. In the remaining 2569 cases, we searched for LMS that were TP53/RB1-wildtype (n=486 of 2569; 18.9%). We also searched LMS tumors for HPV sequences that we then classified into genotypes by de novo assembly of nonhuman sequencing reads followed by alignment to the RefSeq database. Among TP53/RB1-wildtype LMS, we identified 18 unique cases harboring HPV sequences. Surprisingly, most (n=11) were HPV51-positive, and these 11 represented all HPV51-positive tumors in our entire LMS database (n=11 of 2569; 0.4%). The absence of genomic alterations in TP53 or RB1 in HPV51-positive LMS represented a marked difference from HPV51-negative LMS (n=2558; 0% vs. 72% [P<0.00001], 0% vs. 53% [P=0.0002]). In addition, compared with HPV51-negative LMS, HPV51-positive LMS were significantly enriched for genomic alterations in ATRX (55% vs. 24%, P=0.027) and TSC1 (18% vs. 0.6%, P=0.0047). All HPV51-positive LMS were in women; median age was 54 years at surgery (range: 23 to 74 y). All known primary sites were from the gynecologic tract or adjacent anogenital area, including 5 cases of vaginal primary site. Histology was heterogeneous, with evaluable cases showing predominant epithelioid (n=5) and spindle (n=5) morphology. In situ hybridization confirmed the presence of high-risk HPV E6/E7 mRNA in tumor cells in three of three evaluable cases harboring HPV51 genomic sequences. Overall, in our pan-LMS analysis, HPV reads were identified in a subset of TP53/RB1-wildtype LMS. For all HPV51-associated LMS, the striking absence of any detectable TP53 or RB1 mutations and predilection for the female lower reproductive tract supports our hypothesis that high-risk HPV can be an alternative tumorigenic mechanism in this distinct class of LMS.

Case Study of a Rare Incidence of a Leiomyosarcoma Mass Occluding the Distal Femoral Vein

This is a case study of a 47-year-old Caucasian male whose chief concern was left lower leg swelling for 1 month. A unilateral lower extremity venous duplex examination was performed. The results concluded that the distal femoral vein was occluded to the distal popliteal vein. Incidentally, a hypoechoic region in the distal thigh near the distal femoral artery was noted by the technologist. The patient was placed on anticoagulation and was told to return for further examination if there was no relief. Three months later, the patient continued to experience lower left leg swelling and returned for another sonogram. The hypoechoic region was seen again in the distal thigh and remained occluded. A computed tomographic arterial (CT-A) and magnetic resonance imaging (MRI) were ordered for further investigation of the hypoechoic area. The CT-A and the MRI revealed the presence of a mass in the distal thigh. The mass was biopsied and diagnosed as a leiomyosarcoma, grade 1. The mass caused the compression and occlusion of the distal femoral vein. The mass was removed, along with a portion of the distal femoral artery due to involvement of the artery within the mass. The artery was repaired with a graft.

Prognostic value of pretreatment anemia in patients with soft tissue sarcoma: A meta-analysis

BACKGROUND

Anemia is one of the most common manifestations in patients with cancer. Recently, multiple studies have shown a positive correlation between pretreatment anemia and tumor prognosis. Yet, the relationship between pretreatment anemia and the prognosis of soft tissue sarcomas (STS) is unclear.

METHODS

We searched the PubMed and EMBASE databases to identify relevant studies. Eligible studies were included according to the inclusion criteria to assess the relationship between pretreatment anemia and the prognosis of patients with STS. Prognostic significance was determined by studying hazard ratios (HR) and 95% confidence intervals (CIs).

RESULTS

A total of 12 studies are included. If there is significant heterogeneity, a random-effects model is used. Pooled data indicated that pretreatment anemia is related to poor overall survival (HR = 2.13; 95%CI = 1.52-2.98), disease-specific survival (HR = 1.53; 95%CI = 1.20-1.96), and disease-free survival (HR = 1.55; 95%CI = 1.10-2.17). The results of the subgroup analysis also support this conclusion.

CONCLUSION

Our results suggest that pretreatment anemia may be a prognostic biomarker for STS.

Pelvic Leiomyosarcoma With Splenic Metastasis and Response Assessment by 18F-FDG PET/CT

The pelvis is a rare site for the origin of soft tissue sarcomas, and leiomyosarcoma remains the most common soft tissue sarcoma arising in the pelvis. Pelvic leiomyosarcomas are frequently aggressive tumors, and metastatic recurrence rates are high, with the lung, peritoneum, bone, and liver being the most frequent sites. We describe the findings of serial F-FDG PET/CT in a 53-year-old woman having pelvic leiomyosarcoma with uncommon site of metastasis, emphasizing the role of F-FDG PET/CT in response assessment.

CDKN2C-Null Leiomyosarcoma: A Novel, Genomically Distinct Class of TP53/RB1-Wild-Type Tumor With Frequent CIC Genomic Alterations and 1p/19q-Codeletion

PURPOSE

Leiomyosarcoma (LMS) harbors frequent mutations in TP53 and RB1 but few actionable genomic alterations. Here, we searched for recurrent actionable genomic alterations in LMS that occur in the absence of common untreatable oncogenic drivers.

METHODS

Tissues from 276,645 unique advanced cancers, including 2,570 uterine and soft tissue LMS, were sequenced by hybrid-capture-based next-generation DNA and RNA sequencing/comprehensive genomic profiling of up to 406 genes. We characterized clinicopathologic features of relevant patient cases.

RESULTS

Overall, 77 LMS exhibited homozygous copy loss of CDKN2C at chromosome 1p32.3 (3.0% of LMS). Genomic alterations (GAs) in TP53, RB1, and ATRX were rare compared with the remainder of the LMS cohort (11.7% v 73.4%, 0% v 54.5%, 2.6% v 24.5%, respectively; all P < .0001). CDKN2C-null LMS patient cases were significantly enriched for GAs in CIC (40.3% v 1.4%) at 19q13.2, CDKN2A (46.8% v 7.0%), and RAD51B (16.9% v 1.7%; all P < .0001). Chromosome arm-level aneuploidy analysis of available LMS patient cases (n = 1,284) found that 81% (58 of 72) of CDKN2C-null LMS exhibited 1p/19q-codeletion, a significant enrichment compared with 5.1% in the remainder of the LMS cohort (P < .0001). In total, 99% of CDKN2C-null LMS were in women; the median age was 61 years at surgery (range, 36-81 years). Fifty-five patient cases were uterine primary, four were nonuterine, and the remaining 18 were of uncertain primary site. Sixty percent of cases showed at least focal epithelioid variant histology. Most patients had advanced-stage disease, with 62% of confirmed uterine primary LMS at International Federation of Gynecology and Obstetrics stage IVB. We further validated our findings in two publicly available datasets: The Cancer Genome Atlas and the Project GENIE initiative.

CONCLUSION

CDKN2C-null LMS defines a genomically distinct tumor that may have prognostic and/or therapeutic clinical implications, including possible use of specific cyclin-dependent kinase inhibitors.

Phase I studies of vorinostat with ixazomib or pazopanib imply a role of antiangiogenesis-based therapy for TP53 mutant malignancies

We performed two phase I trials of the histone deacetylase inhibitor vorinostat combined with either the vascular endothelial growth factor inhibitor pazopanib (NCT01339871) or the proteasome inhibitor ixazomib (NCT02042989) in patients with metastatic TP53 mutant solid tumors. Both trials followed a 3 + 3 dose-escalation design allowing for a dose expansion cohort of up to 14 additional patients with a specific tumor type. Patients had to have a confirmed TP53 mutation to be enrolled in NCT02042989. Among patients enrolled in NCT01339871, TP53 mutation status was determined for those for whom tumor specimens were available. The results of NCT01339871 were reported previously. Common treatment-related adverse events in NCT02042989 included anemia, thrombocytopenia, fatigue, nausea, vomiting, and diarrhea. Compared with patients with metastatic TP53 hotspot mutant solid tumors who were treated with ixazomib and vorinostat (n = 59), those who were treated with pazopanib and vorinostat (n = 11) had a significantly higher rate of clinical benefit, defined as stable disease lasting ≥6 months or an objective response (3.4% vs. 45%; p < 0.001), a significantly longer median progression-free survival duration (1.7 months [95% confidence interval (CI), 1.1–2.3] vs. 3.5 months [95% CI, 1.7–5.2]; p = 0.002), and a longer median overall survival duration (7.3 months [95% CI, 4.8–9.8] vs. 12.7 months [95% CI, 7.1–18.3]; p = 0.24). Our two phase I trials provide preliminary evidence supporting the use of antiangiogenisis-based therapy in patients with metastatic TP53 mutant solid tumors, especially in those with metastatic sarcoma or metastatic colorectal cancer.

Precision Oncology in Sarcomas: Divide and Conquer

Sarcomas are a heterogeneous group of rare malignancies that exhibit remarkable heterogeneity, with more than 50 subtypes recognized. Advances in next-generation sequencing technology have resulted in the discovery of genetic events in these mesenchymal tumors, which in addition to enhancing understanding of the biology, have opened up avenues for molecularly targeted therapy and immunotherapy. This review focuses on how incorporation of next-generation sequencing has affected drug development in sarcomas and strategies for optimizing precision oncology for these rare cancers. In a significant percentage of soft tissue sarcomas, which represent up to 40% of all sarcomas, specific driver molecular abnormalities have been identified. The challenge to evaluate these mutations across rare cancer subtypes requires the careful characterization of these genetic alterations to further define compelling drivers with therapeutic implications. Novel models of clinical trial design also are needed. This shift would entail sustained efforts by the sarcoma community to move from one-size-fits-all trials, in which all sarcomas are treated similarly, to divide-and-conquer subtype-specific strategies.

Mocetinostat combined with gemcitabine for the treatment of leiomyosarcoma: Preclinical correlates

Leiomyosarcoma (LMS) is a malignant soft tissue sarcoma (STS) with a dismal prognosis following metastatic disease. Chemotherapeutic intervention has demonstrated to have modest clinical efficacy with no curative potential in LMS patients. Previously, we demonstrated pan-HDAC inhibition to have a superior effect in various complex karyotypic sarcomas. In this study, our goal is to evaluate the therapeutic efficacy of mocetinostat alone and in combination with gemcitabine in LMS. Human leiomyosarcoma (LMS) cell lines were used for in vitro and in vivo studies. Compounds tested included the class I HDAC inhibitor, mocetinostat, and nucleoside analog, gemcitabine. MTS and clonogenic assays were used to evaluate the effect of mocetinostat on LMS cell growth. Cleaved caspase 3/7 analysis was used to determine the effects of mocetinostat on apoptosis. Compusyn software was used to determine in vitro synergy studies for the combination of mocetinostat plus gemcitabine. A LMS xenograft model in SCID mice was used to test the impact of mocetinostat alone, gemcitabine alone and the combination of mocetinostat plus gemcitabine. Mocetinostat abrogated LMS cell growth and clonogenic potential, and enhanced apoptosis in LMS cell lines. The combination of mocetinostat plus gemcitabine exhibited a synergistic effect in LMS cells in vitro. Similarly, mocetinostat combined with gemcitabine resulted in superior anti-LMS effects in vivo. Mocetinostat reduced the expression of gemcitabine-resistance markers RRM1, RRM2, and increased the expression of gemcitabine-sensitivity marker, hENT1, in LMS cells. LMS are aggressive, metastatic tumors with poor prognosis where effective therapeutic interventions are wanting. Our studies demonstrate the potential utility of mocetinostat combined with gemcitabine for the treatment of LMS.

Next-Generation Sequencing for Patients with Sarcoma: A Single Center Experience

BACKGROUND

Sarcomas comprise over 50 subtypes of mesenchymal cancers. For the majority of sarcomas, the driver mutations remain unknown. In this article, we describe our experience with a targeted next-generation sequencing (NGS) platform in clinic patients.

MATERIALS AND METHODS

We retrospectively analyzed results of NGS using 133 tumor samples from patients diagnosed with a variety of sarcomas that were analyzed with targeted NGS covering over 400 cancer-related genes (405 DNA, 265 RNA) on a commercially available platform.

RESULTS

An average of two gene alterations were identified per tumor sample (range 0-14), and a total of 342 DNA mutations were detected. Eight-eight percent of samples had at least one detected mutation. The most common mutations were in the cell cycle, including TP53 (n = 35), CDKN2A/B (n = 23), and RB1 (n = 19). Twenty-seven PI3-kinase pathway alterations were observed, including PTEN (n = 14), PIK3Ca (n = 4), TSC1 (n = 1), TSC2 (n = 3), STK11 (n = 1), mTOR (n = 3), and RICTOR (n = 2). There were 75 mutations in genes that are targetable with existing drugs (excluding KIT in gastrointestinal stromal tumor) that would allow enrollment onto clinical trials. In general, the estimated tumor mutation burden was low, in particular for those with disease-defining gene fusions or genetic alterations. Microsatellite instability (MSI) data were available for 50 patients, and all were MSI stable.

CONCLUSION

Our study describes a single-center experience with targeted NGS for patients with sarcoma. Mutations were readily detected and 75 (representing 40% of patients) were testable for therapeutic effect using existing drugs within the confines of a clinical trial. These data indicate that targeted NGS is a useful tool in potentially routing patients to mutation-specific clinical trials. Further study will be required to determine if these mutations are clinically meaningful drug targets in sarcoma.

IMPLICATIONS FOR PRACTICE

The sarcomas are a heterogenous family of over 50 different mesenchymal tumors. Current practice for metastatic disease involves systemic chemotherapy or nonspecific kinase inhibitors such as pazopanib. Sarcomas typically lack the classic kinase alterations seen in many carcinomas. The role of next-generation sequencing in sarcoma clinical practice remains undefined.

Oncopig Soft-Tissue Sarcomas Recapitulate Key Transcriptional Features of Human Sarcomas

Human soft-tissue sarcomas (STS) are rare mesenchymal tumors with a 5-year survival rate of 50%, highlighting the need for further STS research. Research has been hampered by limited human sarcoma cell line availability and the large number of STS subtypes, making development of STS cell lines and animal models representative of the diverse human STS subtypes critical. Pigs represent ideal human disease models due to their similar size, anatomy, metabolism, and genetics compared to humans. The Oncopig encodes inducible KRAS^G12D and TP53^R167H transgenes, allowing for STS modeling in a spatial and temporal manner. This study utilized Oncopig STS cell line (fibroblast) and tumor (leiomyosarcoma) RNA-seq data to compare Oncopig and human STS expression profiles. Altered expression of 3,360 and 7,652 genes was identified in Oncopig STS cell lines and leiomyosarcomas, respectively. Transcriptional hallmarks of human STS were observed in Oncopig STS, including altered TP53 signaling, Wnt signaling activation, and evidence of epigenetic reprogramming. Furthermore, master regulators of Oncopig STS expression were identified, including FOSL1, which was previously identified as a potential human STS therapeutic target. These results demonstrate the Oncopig STS model’s ability to mimic human STS transcriptional profiles, providing a valuable resource for sarcoma research and cell line development.

Survival of patients with metastatic leiomyosarcoma: the MD Anderson Clinical Center for targeted therapy experience

Advanced stage leiomyosarcoma (LMS) is incurable with current systemic antitumor therapies. Therefore, there is clinical interest in exploring novel therapeutic regimens to treat LMS. We reviewed the medical records of 75 consecutive patients with histologically confirmed metastatic LMS, who had been referred to the Clinical Center for Targeted Therapy at MD Anderson Cancer Center. To lay the foundation for potential phase I trials for the treatment of advanced LMS, we analyzed tumor response and survival outcome data. The frequent hotspot gene aberrations that we observed were the TP53 mutation (65%) and RB1 loss/mutation (45%) detected by Sequenom or next-generation sequencing. Among patients treated with gene aberration-related phase I trial therapy, the median progression-free survival was 5.8 months and the median overall survival was 15.9 months, significantly better than in patients without therapy (1.9 months, P = 0.001; and 8.7 months, P = 0.013, respectively). Independent risk factors that predicted shorter overall survival included hemoglobin <10 g/dL, body mass index <30 kg/m2 , serum albumin <3.5 g/dL, and neutrophil above upper limit of normal. The median survivals were 19.9, 7.6, and 0.9 months for patients with 0, 1 or 2, and ≥3 of the above risk factors, respectively (P < 0.001). A prognostic scoring system that included four independent risk factors might predict survival in patients with metastatic LMS who were treated in a phase I trial. Gene aberration-related therapies led to significantly better clinical benefits, supporting that further exploration with novel mechanism-driven therapeutic regimens is warranted.