Uterine leiomyomas, or fibroids, are very common smooth muscle tumors that arise from the myometrium. They can be divided into distinct molecular subtypes. We have previously shown that ...3′RNA‐sequencing is highly effective in classifying archival formalin‐fixed paraffin‐embedded (FFPE) leiomyomas according to the underlying mutation. In this study, we performed 3′RNA‐sequencing with 111 FFPE leiomyomas previously classified as negative for driver alterations in mediator complex subunit 12 (MED12), high mobility group AT‐hook 2 (HMGA2), and fumarate hydratase (FH) by Sanger sequencing and immunohistochemistry. This revealed 43 tumors that displayed expression features typically seen in HMGA2‐positive tumors, including overexpression of PLAG1. We explored 12 such leiomyomas by whole‐genome sequencing to identify their underlying genomic drivers and to evaluate the feasibility of detecting chromosomal driver alterations from FFPE material. Four tumors with significant HMGA2 overexpression at the protein‐level served as controls. We identified chromosomal rearrangements targeting either HMGA2, HMGA1, or PLAG1 in all 16 tumors, demonstrating that it is possible to detect chromosomal driver alterations in archival leiomyoma specimens as old as 18 years. Furthermore, two tumors displayed biallelic loss of DEPDC5 and one tumor harbored a COL4A5–COL4A6 deletion. These observations suggest that instead of only HMGA2‐positive leiomyomas, a distinct leiomyoma subtype is characterized by rearrangements targeting either HMGA2, HMGA1, or PLAG1. The results indicate that the frequency of HMGA2‐positive leiomyomas may be higher than estimated in previous studies where immunohistochemistry has been used. This study also demonstrates the feasibility of detecting chromosomal driver alterations from archival FFPE material.
Uterine leiomyomas, or fibroids, are very common smooth muscle tumors. Their potential to metastasize or transform into leiomyosarcomas is extremely low. Here, we report a patient who underwent ...hysterectomy due to a large leiomyoma and who was diagnosed with pulmonary tumors seven and nine years later. Histopathological re-evaluation confirmed the cellular leiomyoma diagnosis for the uterine tumor, whereas the pulmonary tumors met the diagnostic criteria of a leiomyosarcoma. Whole-exome sequencing revealed very similar mutational profiles in all three tumors, including a somatic homozygous deletion in a rare, but well-established leiomyoma driver gene FH. Tumor evolution analysis confirmed the clonal origin of all three tumors. In addition to mutations shared by all three tumors, pulmonary tumors harbored additional alterations affecting e.g. the cancer-associated genes NRG1 and MYOCD. The second pulmonary leiomyosarcoma harbored additional changes, including a mutation in FGFR1. In global gene expression profiling, the uterine tumor showed similar expression patterns as other FH-deficient leiomyomas. Taken together, this comprehensive molecular data supports the occasional metastatic capability and malignant transformation of uterine leiomyomas. Further studies are required to confirm whether FH-deficient tumors and/or tumors with cellular histopathology have higher malignant potential than other uterine leiomyomas.
Abstract
Uterine leiomyomas, or fibroids, are the most common tumors in women of reproductive age. Uterine leiomyomas can be classified into at least three main molecular subtypes according to ...mutations affecting
MED12
,
HMGA2
, or
FH
. FH-deficient leiomyomas are characterized by activation of the NRF2 pathway, including upregulation of the NRF2 target gene
AKR1B10
. Here, we have identified a novel leiomyoma subtype showing AKR1B10 expression but no alterations in
FH
or other known driver genes. Whole-exome and whole-genome sequencing revealed biallelic mutations in key genes involved in neddylation of the Cullin 3-RING E3 ligase, including
UBE2M
,
NEDD8
,
CUL3
, and
NAE1
. 3′RNA sequencing confirmed a distinct molecular subtype with activation of the NRF2 pathway. Most tumors displayed cellular histopathology, perivascular hypercellularity, and characteristics typically seen in FH-deficient leiomyomas. These results suggest a novel leiomyoma subtype that is characterized by distinct morphological features, genetic alterations disrupting neddylation of the Cullin 3-RING E3 ligase, and oncogenic NRF2 activation. They also present defective neddylation as a novel mechanism leading to aberrant NRF2 signaling. Molecular characterization of uterine leiomyomas provides novel opportunities for targeted treatment options.
Repeat leiomyoma occurrence or even reintervention is common after myomectomy. Little is known about the factors related to repeat interventions.
This study aimed to determine the frequency of ...leiomyoma-related reintervention after an initial laparoscopic or abdominal myomectomy and to analyze both clinical and molecular risk factors for reinterventions. Another objective was to define the frequency of clonally related tumors from repeat operations.
This retrospective cohort study included 234 women who had undergone laparoscopic or abdominal myomectomy in 2009-2014. Information on repeat leiomyoma-related interventions as well as on other clinical factors was collected from medical records after a median follow-up time of 11,4 years (range 7,9-13,8 years) after the index procedure. The effect of clinical risk factors on the risk of reintervention was analyzed by the Kaplan-Meier estimator and the Cox proportional hazards model. For molecular analyses, we examined the mutation profiles of 133 formalin-fixed paraffin-embedded leiomyoma samples from 33 patients with repeat operations. We screened the tumors for the three primary leiomyoma driver alterations—MED12 mutations, HMGA2 overexpression, and FH-deficiency—utilizing Sanger sequencing and immunohistochemistry. To further assess the clonal relationship of the tumors, we executed whole-exome sequencing for 52 leiomyomas from 21 patients who exhibited the same driver alteration in tumors obtained from multiple procedures.
Reintervention rate at 11,4 years after myomectomy was 20% (46/234). Number of leiomyomas removed at the index myomectomy was a risk factor (hazard ratio 1.21; 95% confidence interval 1.09-1.34). Age at index myomectomy (hazard ratio 0.94; 95% confidence interval 0.89-0.99) and postoperative parity (hazard ratio 0.23; 95% confidence interval 0.09-0.60) were protective factors. Molecular characterization of tumors from index and non-index operations confirmed a clonal relationship of the tumors in 3/33 (9%) patients. None of the leiomyomas harboring a MED12 mutation —the most common leiomyoma driver— were confirmed clonally related. FH-deficiency was detected in repeat leiomyomas from 3/33 (9%) patients. All these patients harbored a germline FH mutation, which is distinctive for the hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome. Finally, we identified three (3/33; 9%) patients with two tumors each displaying somatic mutations in a recently identified novel leiomyoma driver gene, YEATS4. All YEATS4 mutations were different and thus the tumors were not clonally related.
Our study shows that reintervention is common after surgical myomectomy. Uterine leiomyomas typically develop independently, but some share a clonal origin. Repeat leiomyoma occurrence may be due to genetic predisposition, such as a germline FH mutation. Distinct somatic YEATS4 mutations identified in multiple leiomyomas from the same patient indicate a possible role for YEATS4 in repeat leiomyomas.
Uterine leiomyomas are benign smooth muscle tumors occurring in 70% of women of reproductive age. The majority of leiomyomas harbor one of three well-established genetic changes: a hotspot mutation ...in MED12, overexpression of HMGA2, or biallelic loss of FH. The majority of studies have classified leiomyomas by complex and costly methods, such as whole-genome sequencing, or by combining multiple traditional methods, such as immunohistochemistry and Sanger sequencing. The type of specimens and the amount of resources available often determine the choice. A more universal, cost-effective, and scalable method for classifying leiomyomas is needed. The aim of this study was to evaluate whether RNA sequencing can accurately classify formalin-fixed paraffin-embedded (FFPE) leiomyomas. We performed 3′RNA sequencing with 44 leiomyoma and 5 myometrium FFPE samples, revealing that the samples clustered according to the mutation status of MED12, HMGA2, and FH. Furthermore, we confirmed each subtype in a publicly available fresh frozen dataset. These results indicate that a targeted 3′RNA sequencing panel could serve as a cost-effective and robust tool for stratifying both fresh frozen and FFPE leiomyomas. This study also highlights 3′RNA sequencing as a promising method for studying the abundance of unexploited tissue material that is routinely stored in hospital archives.
Abstract
Uterine adenomyosis is a condition in which ectopic endometrial glands are present in myometrial stroma surrounded by smooth muscle cell hyperplasia. Foci of adenomyosis growing as a tumor ...like mass are called adenomyomas. Uterine adenomyomas are common tumors and they share symptoms, including pelvic pain and abnormal bleeding, with uterine leiomyomas. The two tumor types are challenging to distinguish from one another and the diagnosis is usually confirmed only after surgery by pathological evaluation. The molecular background of uterine adenomyomas is not currently well known. In uterine leiomyomas, somatic mediator complex subunit 12 (MED12) mutations, high mobility group AT-hook (HMGA2) protein overexpression, and fumarate hydratase (FH) inactivation are well established as major mutually exclusive driver events covering 80-90% of the tumors. Here, we have analyzed the presence of these changes in a set of 21 uterine adenomyomas. Representative areas of formalin-fixed paraffin embedded archival uterine adenomyoma tissue samples were used to construct a tissue microarray. The HMGA2 overexpression and the FH inactivation were assessed using immunohistochemistry with anti HMGA and 2SC antibodies, respectively. DNA was extracted from the tumor samples to determine the MED12 mutation status by direct sequencing of exons 1 and 2 of the gene. MED12 c.131GA, p.G44D mutation was found in two adenomyoma samples out of 21 (9.5%). Strong positive staining of 2SC indicating FH inactivation was present in one sample which also showed reduced FH protein expression when validated with an independent method using anti-FH immunostaining. Sequencing revealed a frameshift mutation c.911delC, p.P304fs in exon 7 leading to a premature stop codon 25 codons later. The mutation was also found in a separate uterine leiomyoma of the same patient and both tumor samples mostly presented the mutant allele indicating loss of heterozygosity of the wild type allele. This, together with the patient's medical history of previous uterine leiomyomas, indicates the germline origin of the mutation and thus a hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome. No changes in HMGA2 expression were detected with all samples presenting normal expression levels. In conclusion, MED12 mutations are present in a subset of uterine adenomyomas. The mutation frequency of 9.5% that was observed here in our adenomyoma sample series is considerably lower than that of 70% in uterine leiomyomas. Our results also suggest that adenomyomas may be linked to HLRCC in which they have not been previously reported. The driver events behind uterine adenomyomas remain mostly unknown and further large-scale studies are warranted to clarify the spectrum of underlying mutations and molecular background of these common tumors.
Citation Format: Tuomas A. Heikkinen, Anna Äyräväinen, Janne Hänninen, Terhi Ahvenainen, Ralf Bützow, Annukka Pasanen, Pia Vahteristo. Uterine leiomyoma driver events in uterine adenomyomas abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4611.
Abstract Uterine leiomyomas, also known as fibroids, are common benign smooth muscle tumors in women of reproductive age. Leiomyomas can cause symptoms that can significantly reduce the quality of ...life. Treatment mainly involves hysterectomy or myomectomy, the latter for women who wish to preserve their uterus. Most leiomyomas harbor one of the three driver mutations affecting either MED12, HMGA2, or FH. Recently identified rare subtypes include tumors with mutations in genes linked to the neddylation of the Cullin 3-RING E3 ligase or SRCAP complex. Recurrence of leiomyomas is poorly understood in relation to their clonal origins and molecular factors. The aim of this study was to characterize the mutational profiles of leiomyomas from recurrent operations and to identify the frequency of clonally related tumors. We utilized a retrospective cohort of 234 women who underwent laparoscopic or open abdominal myomectomy, with 46 (20%) of them experiencing multiple procedures related to leiomyomas. We examined the mutation profiles of 133 leiomyomas (62 index and 71 recurrent tumors) from 33 patients who required multiple tumor removal surgeries. We screened the tumors for the three primary leiomyoma drivers—MED12 mutations, HMGA2 overexpression, and FH-deficiency—to identify potentially clonal tumors. We found that 21 out of 33 (64%) patients had tumors from multiple operations with identical leiomyoma driver alterations. To further assess the clonal relationship, we executed whole exome sequencing on these 52 tumors. We identified three patients with two clonally related tumors each through shared somatic copy number alterations and point mutations. The clonally related tumors included HMGA2, FH, and wild-type tumors. Notably, leiomyomas with MED12 mutations—the most common molecular leiomyoma subtype—were not found among the clonally related tumors. Three patients harbored numerous FH-deficient tumors from recurrent operations. In all those patients, we found FH germline mutations, characteristic of Hereditary Leiomyomatosis and Renal Cell Cancer syndrome (HLRCC). Moreover, we identified somatic mutations in YEATS4, a member of the SRCAP complex, in four recurrent tumors from three patients. Interestingly, all YEATS4 mutations were different, and the tumors were not clonally related. Further research is required to elucidate the role of YEATS4 in leiomyoma recurrence. In conclusion, our systematic study confirms that reinterventions are common after myomectomy, and while uterine leiomyomas typically develop independently, some share a clonal origin. Additionally, we show that recurrence may be due to genetic predispositions, such as germline FH mutations. Citation Format: Sara Khamaiseh, Anna Äyräväinen, Maare Arffman, Siiri Reinikka, Annukka Pasanen, Ralf Bützow, Päivi Härkki, Pia Vahteristo. Genetic background of recurrent uterine leiomyomas abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5055.
Uterine leiomyomas are benign smooth muscle tumors occurring in 70% of women of reproductive age. The majority of leiomyomas harbor one of three well-established genetic changes: a hotspot mutation ...in
, overexpression of
, or biallelic loss of
. The majority of studies have classified leiomyomas by complex and costly methods, such as whole-genome sequencing, or by combining multiple traditional methods, such as immunohistochemistry and Sanger sequencing. The type of specimens and the amount of resources available often determine the choice. A more universal, cost-effective, and scalable method for classifying leiomyomas is needed. The aim of this study was to evaluate whether RNA sequencing can accurately classify formalin-fixed paraffin-embedded (FFPE) leiomyomas. We performed 3'RNA sequencing with 44 leiomyoma and 5 myometrium FFPE samples, revealing that the samples clustered according to the mutation status of
,
, and
. Furthermore, we confirmed each subtype in a publicly available fresh frozen dataset. These results indicate that a targeted 3'RNA sequencing panel could serve as a cost-effective and robust tool for stratifying both fresh frozen and FFPE leiomyomas. This study also highlights 3'RNA sequencing as a promising method for studying the abundance of unexploited tissue material that is routinely stored in hospital archives.
Do the uterine leiomyoma driver events - mediator complex subunit 12 (
) mutations, high mobility group AT-hook (HMGA2) overexpression, and fumarate hydratase (FH) inactivation - also contribute to ...the development of uterine adenomyomas?
mutations and FH deficiency occur in a subset of uterine adenomyomas, but at lower frequencies than in leiomyomas.
Uterine adenomyomas are benign tumours with clinical features very similar to uterine leiomyomas. Mutations affecting
,
and
account for up to 80-90% of leiomyomas, but their contribution to adenomyomas is not known.
Formalin-fixed paraffin-embedded adenomyoma samples from 21 patients operated on during 2012-2014 were collected at the pathology department's archives and analysed for uterine leiomyoma driver events.
Adenomyoma diagnoses were verified by a specialized pathologist and representative areas were marked on haematoxylin-eosin slides. DNA was extracted from the tissue samples and sequenced to detect mutations in
. Expression levels of HMGA2 and 2SC, a robust indirect method to detect FH inactivation, were analysed by immunohistochemistry (IHC). The coding region of
was sequenced in one adenomyoma sample showing strong 2SC staining as well as in the same patient's normal tissue sample. All patients' medical histories were collected and reviewed.
mutation c.131G > A, p.G44D, the most common mutation in uterine leiomyomas, was identified in two samples (2/21; 9.5%). One adenomyoma displayed strong 2SC positivity and subsequent sequencing revealed a frameshift
mutation c.911delC, p.P304fs in the tumour. The mutation was also present in the patient's normal tissue sample, indicating that she has a hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome. HMGA2 protein expression was normal in all adenomyomas.
Restricted sample size limits the determination of exact mutation frequencies of the studied aberrations in adenomyomas.
Uterine leiomyoma driver mutations do contribute to the development of some adenomyomas. We also report an adenomyoma in the context of hereditary HLRCC syndrome. Despite clinical similarities, the pathogenic mechanisms of adenomyomas and leiomyomas are likely different. Large-scale genomic analyses are warranted to elucidate the complete molecular background of adenomyomas.
This study was supported by The Academy of Finland, the Sigrid Jusélius Foundation, and the Cancer Society of Finland. The authors declare no conflict of interest.
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