Genomic profile analysis of leiomyomas with bizarre nuclei and fumarate hydratase deficient leiomyomas: Strengths, weaknesses, and limitations of array-CGH interpretation.

A close relationship has been demonstrated between genomic complexity and clinical outcome in uterine smooth muscle tumors. We studied the genomic profiles by array-CGH of 28 fumarate hydratase deficient leiomyomas and 37 leiomyomas with bizarre nuclei (LMBN) from 64 patients. Follow-up was available for 46 patients (from three to 249 months, mean 87.3 months). All patients were alive without evidence of disease. For 51 array-CGH interpretable tumors the mean Genomic Index (GI) was 16.4 (median: 9.8; from 1 to 57.8), significantly lower than the mean GI in LMS (mean GI 51.8, p < 0.001). We described three groups: (1) a group with FH deletion (24/58) with low GI (mean GI: 11 vs. 22,4, p = 0.02), (2) a group with TP53 deletion (17/58) with higher GI (22.4 vs. 11 p = 0.02), and (3) a group without genomic events on FH or TP53 genes (17/58) (mean GI:18.3; from 1 to 57.8). Because none of these tumors recurred and none showed morphological features of LMS we concluded that GI at the cut-off of 10 was not applicable in these subtypes of LM. By integration of all those findings, a GI <10 in LMBN remains a valuable argument for benignity. Conversely, in LMBN a GI >10 or alteration in tumor suppressor genes, should not alone warrant a diagnosis of malignancy. Nine tumors were tested with Nanocind CINSARC® signature and all were classified in low risk of recurrence. We propose, based on our observations, a diagnostic approach of these challenging lesions.

Atypical Spindle Cell/Pleomorphic Lipomatous Tumor With Sarcomatous Transformation: Clinicopathologic and Molecular Analysis of 4 Cases.

Atypical spindle cell/pleomorphic lipomatous tumor (ASPLT) is a recently described adipocytic tumor predominantly affecting the subcutaneous soft tissues of adults. Previous studies have shown that ASPLT follows a benign clinical course with a 4% to 12% local recurrence rate and no risk of dedifferentiation. Herein, we describe the clinicopathologic and molecular findings of 4 cases of ASPLT showing unequivocal sarcomatous transformation. Three patients were male and one was female, aged 65, 70, 74, and 78 years. Two cases presented as mass-forming lesions, while 1 case was incidentally discovered. The tumors measured 30, 55, 80, and 110 mm and occurred in the chest wall (n = 2) or arm (n = 2); all were subcutaneous. Microscopically, they showed a biphasic appearance comprising a low-grade ASPLT component and a high-grade sarcomatous component. The low-grade components showed features in the spectrum of either atypical pleomorphic lipomatous tumor (n = 2) or atypical spindle cell lipomatous tumor (n = 2). The high-grade components displayed leiomyosarcoma-like (n = 2), pleomorphic liposarcoma-like (n = 1) or undifferentiated sarcoma-like (n = 1) morphology. On immunohistochemistry, tumors were negative for MDM2 and showed loss of RB1 expression. In addition, the leiomyosarcoma-like areas seen in 2 cases were positive for smooth muscle actin and H-caldesmon. Single-nucleotide polymorphism array, performed in 3 cases, showed deletions of TP53, RB1, and flanking genes in both components. In contrast, the sarcomatous components showed more complex genomic profiles with rare segmental gains and recurrent loss of PTEN (n = 3), ATM (n = 2), and CDKN2A/B (n = 2) among other genes. Whole exome sequencing identified a TP53 variant in one case and an ATRX variant in another, each occurring in both tumor components. Limited clinical follow-up showed no recurrence or metastasis after 1 to 13 months (median, 7.5 months) postsurgical excision. Altogether, our data support that ASPLT can rarely develop sarcomatous transformation and offer insights into the molecular mechanisms underlying this event.

The KAT6B::KANSL1 Fusion Defines a New Uterine Sarcoma With Hybrid Endometrial Stromal Tumor and Smooth Muscle Tumor Features.

Neoplasms harboring a KAT6B/A::KANSL1 fusion were initially reported as benign (leiomyomas) and malignant (leiomyosarcomas, low-grade endometrial stromal sarcomas [LG-ESSs]) uterine neoplasms. However, they may represent an emerging entity characterized by clinical aggressiveness contrasting with a rather reassuring microscopic appearance. Here, we aimed to confirm that this neoplasm is a distinct clinicopathologic and molecular sarcoma and identify criteria that should alert pathologists and lead to KAT6B/A::KANSL1 fusion testing in routine practice. Therefore, we conducted a comprehensive clinical, histopathologic, immunohistochemical, and molecular study, including array comparative genomic hybridization, whole RNA-sequencing, unsupervised clustering, and cDNA mutational profile analyses of 16 tumors with KAT6B::KANSL1 fusion from 12 patients. At presentation, patients were peri-menopausal (median, 47.5 years), and the primary tumors were located in the uterine corpus (12/12, 100%), with an additional prevesical location in 1 (8.3%) of 12 cases. The relapse rate was 33.3% (3/9). All tumors (16/16, 100%) showed morphologic and immunohistochemical features overlapping between leiomyoma and endometrial stromal tumors. A whirling recurrent architecture (resembling fibromyxoid-ESS/fibrosarcoma) was found in 13 (81.3%) of 16 tumors. All tumors (16/16, 100%) exhibited numerous arterioliform vessels, and 13 (81.3%) of 18 had large hyalinized central vessels and collagen deposits. Estrogen and progesterone receptors were expressed in 16 (100%) of 16 and 14 (87.5%) of 16 tumors, respectively. Array comparative genomic hybridization performed on 10 tumors classified these neoplasms as simple genomic sarcomas. Whole RNA-sequencing on 16 samples and clustering analysis on primary tumors found that the KAT6B::KANSL1 fusion always occurred between exons 3 of KAT6B and 11 of KANSL1; no pathogenic variant was identified on cDNA, all neoplasms clustered together, close to LG-ESS, and pathway enrichment analysis showed cell proliferation and immune infiltrate recruitment pathway involvement. These results confirm that the sarcomas harboring a KAT6B/A::KANSL1 fusion represent a distinct clinicopathologic entity, close to LG-ESS but different, with clinical aggressiveness despite a reassuring morphology, for which the KAT6B/A::KANSL1 fusion is the molecular driver alteration.

The Nanocind Signature Is an Independent Prognosticator of Recurrence and Death in Uterine Leiomyosarcomas.

PURPOSE: Uterine leiomyosarcoma, which accounts for 7% of all soft-tissue sarcomas and 1%-3% of all uterine malignancies, is an aggressive tumor responsible for a significant proportion of uterine cancer-related deaths. While Federation Internationale des Gynaecologistes et Obstetristes (FIGO) stage is the most important prognostic factor, metastatic and relapse rates at stage I exceed 50% so it is currently impossible to predict the clinical outcome of stage I leiomyosarcomas. In 2010, our team published a transcriptomic signature composed of 67 genes related to chromosome biogenesis, mitosis control, and chromosome segregation. It has demonstrated its prognostic value in many cancer types and was recently successfully applied to formalin-fixed, paraffin-embedded sarcomas by NanoCind on NanoString technology, making another step forward toward its use in routine practice. EXPERIMENTAL DESIGN: Sixty uterine leiomyosarcomas at any stage, including 40 localized in the uterus (stage I), were analyzed with the NanoCind (CINSARC with NanoString) signature. Its prognostic value was evaluated for overall survival and relapse-free survival and compared in multivariate analysis with other prognostic markers like FIGO staging and genomic index. RESULTS: The NanoCind signature was able to split the heterogeneous group of uterine leiomyosarcomas of any stage including stage I into two distinct groups with different relapse-free survival and overall survival. These results were validated on an independent cohort of uterine leiomyosarcomas in The Cancer Genome Atlas consortium. CONCLUSIONS: The NanoCind signature is a powerful prognosticator that outperforms FIGO staging and the genomic index. The CINSARC signature is platform independent and "ready to use" and should now be used for randomization in future therapeutic trials.

Uterine and vaginal sarcomas resembling fibrosarcoma: a clinicopathological and molecular analysis of 13 cases showing common NTRK-rearrangements and the description of a COL1A1-PDGFB fusion novel to uterine neoplasms.

Mesenchymal neoplasms of the uterus (corpus and cervix) encompass a heterogeneous group of tumors with differing morphologies, immunophenotypes and molecular alterations. With the advent of modern molecular techniques, such as next generation sequencing, newly defined genetic abnormalities are being reported in this group of neoplasms. Herein we report the clinicopathological and molecular features of a series of 13 spindle cell sarcomas of the uterus and vagina (10 cervix, 2 uterine corpus, 1 vagina) with morphology resembling fibrosarcoma. After targeted RNA-sequencing, dual FISH fusion and array-CGH analysis, 7 of 13 tumors exhibited NTRK rearrangements (6 TPM3-NTRK1 and 1 EML4-NTRK3) and 3 a COL1A1-PDGFB fusion; in the other 3 neoplasms, all of which were positive with S100 (2 diffuse, 1 focal), we identified no rearrangement. All the NTRK fusion-positive sarcomas were located in the cervix and exhibited diffuse staining with Trk while all the other neoplasms were negative. CD34 was diffusely positive in all 3 of the COL1A1-PDGFB fusion sarcomas. The latter molecular abnormality is identical to that commonly found in dermatofibrosarcoma protuberans and has not been reported previously in uterine mesenchymal neoplasms. We suggest that uterine sarcomas with a morphology resembling fibrosarcoma (and in which leiomyosarcoma and the known molecularly confirmed high-grade endometrial stromal sarcomas have been excluded) can be divided into 3 groups:- an NTRK fusion group, a COL1A1-PDGFB fusion group and a group containing neither of these molecular abnormalities which, on the basis of positive staining with S100, could be tentatively classified as malignant peripheral nerve sheath tumor, although additional molecular studies may identify specific genetic alterations necessitating a nomenclature change. We suggest a diagnostic algorithm when reporting such neoplasms. Identification of these newly described fusion-associated sarcomas is important given the potential for targeted treatments.

GREB1-CTNNB1 fusion transcript detected by RNA-sequencing in a uterine tumor resembling ovarian sex cord tumor (UTROSCT): A novel CTNNB1 rearrangement.

Mutations of CTNNB1 have been implicated in tumorigenesis in many organs. However, tumors harboring a CTNNB1 translocation are extremely rare and this translocation has never been reported in a uterine mesenchymal neoplasm. We report a novel translocation t(2;3)(p25;p22) involving the GREB1 (intron 8) and CTNNB1 (exon 3) in a uterine tumor resembling ovarian sex cord tumor (UTROSCT), which exhibited extrauterine metastasis. The translocation detected by RNA-sequencing was validated by RT-PCR, and resulted in nuclear expression of ß-catenin. Juxtapositioning with GREB1, which is overexpressed in response to estrogens, resulted in overexpression of a truncated and hypophosphorylated nuclear ß-catenin in the primary and recurrent tumors. This accumulation of nuclear ß-catenin results in a constitutive activation of the Wnt/ß-catenin signaling pathway with a major oncogenic effect. The CTNNB1 gene fusion, promoted by an estrogen-responsive gene (GREB1), could be a potential driver of tumorigenesis in this case and a therapeutic target with adapted inhibitors. RT-PCR and immunohistochemistry performed on 11 additional UTROSCTs showed no CTNNB1 fusion transcript or nuclear ß-catenin immunoreactivity.