No abstract

Liposarcoma remains the most common mesenchymal cancer, with a mortality rate of 60% among patients with this disease. To address the present lack of therapeutic options, we embarked upon a study of microRNA (miRNA) expression alterations associated with liposarcomagenesis with the goal of exploiting differentially expressed miRNAs and the gene products they regulate as potential therapeutic targets. MicroRNA expression was profiled in samples of normal adipose tissue, well-differentiated liposarcoma, and dedifferentiated liposarcoma by both deep sequencing of small RNA libraries and hybridization-based Agilent microarrays. The expression profiles discriminated liposarcoma from normal adipose tissue and well-differentiated from dedifferentiated disease. We defined over 40 miRNAs that were dysregulated in dedifferentiated liposarcomas in both the sequencing and the microarray analysis. The upregulated miRNAs included two cancer-associated species (miR-21, miR-26a), and the downregulated miRNAs included two species that were highly abundant in adipose tissue (miR-143, miR-145). Restoring miR-143 expression in dedifferentiated liposarcoma cells inhibited proliferation, induced apoptosis, and decreased expression of BCL2, TOP2A, PRC1, and PLK1. The downregulation of PRC1 and its docking partner PLK1 suggests that miR-143 inhibits cytokinesis in these cells. In support of this idea, treatment with a PLK1 inhibitor potently induced G2/M growth arrest and apoptosis in liposarcoma cells. Taken together, our findings suggest that miR-143 re-expression vectors or selective agents directed at miR-143 or its targets may have therapeutic value in dedifferentiated liposarcoma.

Liposarcomas are the most common type of soft tissue sarcoma but their genetics are poorly defined. To identify genes that contribute to liposarcomagenesis and serve as prognostic candidates, we undertook expression profiling of 140 primary liposarcoma samples, which were randomly split into training set (n ¼ 95) and test set (n ¼ 45). A multigene predictor for distant recurrence-free survival (DRFS) was developed by the supervised principal component method. Expression levels of the 588 genes in the predictor were used to calculate a risk score for each patient. In validation of the predictor in the test set, patients with low risk score had a 3-year DRFS of 83% versus 45% for high risk score patients (P ¼ 0.001). The HR for high versus low score, adjusted for histologic subtype, was 4.42 (95% CI, 1.26-15.55; P ¼ 0.021). The concordance probability for risk score was 0.732. In contrast, the concordance probability for histologic subtype, which had been considered the best predictor of outcome in liposarcoma, was 0.669. Genes related to adipogenesis, DNA replication, mitosis, and spindle assembly checkpoint control were all highly represented in the multigene predictor. Three genes from the predictor, TOP2A, PTK7, and CHEK1, were found to be overexpressed in liposarcoma samples of all five subtypes and in liposarcoma cell lines. RNAi-mediated knockdown of these genes in liposarcoma cell lines reduced proliferation and invasiveness and increased apoptosis. Taken together, our findings identify genes that seem to be involved in liposarcomagenesis and have promise as therapeutic targets, and support the use of this multigene predictor to improve risk stratification for individual patients with liposarcoma. Cancer Res; 71(7); 2697-705. Ó2011 AACR.

Background The ACOSOG Z0011 trial demonstrated that axillary dissection (ALND) is not necessary for local control or survival in women with T1/2cN0 cancer undergoing breast-conserving therapy. There is concern about applying these results to triple-negative (TN) cancers secondary to their high local-recurrence (LR) rate. We examined the frequency of lymphovascular invasion (LVI) and nodal metastases in TN cancers to determine whether ALND can be safely avoided in this subtype. Methods Data were obtained from a database of patients with invasive breast cancer treated at Memorial Sloan Kettering from 1/98–12/10. 11,596 tumors were classifiable into clinical surrogates for molecular subtype by immunohistochemical analysis: hormone receptor (HR)+/HER2+, HR+/HER2-, HR-/HER2+, and TN(HR-/HER2-). Multivariable logistic regression analysis (MVA)was used to determine associations between clinicopathologic variables and subtype. Results There were differences in age, tumor size, LVI, grade, and nodal involvement among groups. On MVA controlling for size, grade, and age, ER, PR, and HER2 status were significantly associated with LVI(p<.0001). Relative to TN tumors, HR+/HER2-, HR+/HER2+, and HR-/HER2+ tumors had higher odds of demonstrating LVI of 1.8(OR,1.8; 95% CI,1.6–2.1), 2.5(2.5;2.0–3.0), and 1.7(1.7;1.4–2.1), respectively. On MVA adjusting for size, grade, LVI, and age, TN tumors had the lowest odds of having any or high-volume nodal involvement (≥4 nodes, p<.0001). Conclusions LVI and nodal metastases were least frequent in TN cancers compared with other subtypes, despite the uniformly worse prognosis and increased LR rate in TN tumors. This suggests TN cancers spread via lymphatics less frequently than other subtypes and ALND may be avoided in TN patients meeting Z0011 eligibility criteria.

Current preoperative diagnostic procedures for thyroid nodules rely mainly on the cytological interpretation of fine-needle aspirates (FNAs). DNA microarray analysis has been shown to reliably distinguish benign and malignant thyroid nodules in surgically resected specimens, but its diagnostic potential in thyroid FNA has not been examined. In the present study, the expression profiles of 50 benign thyroid lesions and papillary thyroid carcinoma tissue samples were compared, generating a list of 25 differentially expressed genes from this training set. A test set of 22 FNA specimens was evaluated by unsupervised hierarchical cluster analysis using this gene list, and the results were compared to FNA cytology. FNA specimens were found to fall into three clusters: malignant (n ‫؍‬ 10), benign (n ‫؍‬ 7), and indeterminate (n ‫؍‬ 5). The benign and malignant groups showed complete concordance with the final histological diagnosis except for one histologically benign lesion, which was rediagnosed as follicular variant of papillary thyroid carcinoma on histological review. Paired analysis between FNA and matched tissues samples illustrated adequate sampling with FNA. These results illustrate that microarray analysis of FNA is feasible and has the potential to improve the accuracy of FNA in categorizing benign from malignant lesions beyond routine cytological evaluation.

Translocations or mutations of FUS, EWSR1 and TAF15 (FET) result in distinct genetic diseases. N-terminal translocations of any FET protein to a series of transcription factors yields chimeric proteins that contribute to sarcomagenesis, whereas mutations in the conserved C-terminal domain of wild-type FUS were recently shown to cause familial amyotrophic lateral sclerosis. We thus investigated whether the loss of one FUS allele by translocation in liposarcoma may be followed by mutations in either the remaining FUS allele or the paralogous EWSR1. Furthermore, we investigated the strength of the FET promoters and their contributions to sarcomagenesis given the proteins’ frequent involvement in oncogenic translocations. We sequenced the respective genomic regions of both FUS and EWSR1 in 96 liposarcoma samples. Additionally, we determined FET transcript and protein levels in several liposarcoma cell lines. We did not observe sequence variations in either FUS or EWSR1. However, protein copy numbers reached an impressive 0.9 and 5.5 Mio of FUS and EWSR1 per tumor cell, respectively. Compared with adipose-derived stem cells, FUS and EWSR1 protein expression levels were elevated on average 28.6-fold and 7.3-fold, respectively. TAF15 mRNA levels were elevated on average 3.9-fold, though with a larger variation between samples. Interestingly, elevated TAF15 mRNA levels did not translate to strongly elevated protein levels, consistent with its infrequent occurrence as translocation partner in tumors. These results suggest that the powerful promoters of FET genes are predominantly responsible for the oncogenic effect of transcription factor translocations in sarcomas.

Introduction reoperative sentinel lymph node biopsy (SLNB) is feasible in patients with local recurrence (LR) of invasive breast cancer, but it remains unclear if this procedure affects either treatment or outcome. Here we ask whether axillary restaging (versus none) at the time of LR affects the rate of subsequent events: axillary failure, non-axillary recurrence, distant metastasis or death. Methods we queried our institutional database to identify patients treated surgically for invasive breast cancer with a negative SLNB (1997–2000) who developed ipsilateral breast or chest wall recurrence as a first event. We excluded those with gross nodal disease at the time of LR. The cumulative incidence of subsequent events was estimated using competing risks methodology. Results of 1527 patients with negative SLN at initial surgery, 83 had an ipsilateral breast (79) or chest wall recurrence (4) with clinically negative regional nodes. 47 (57%) were treated with and 36 (43%) without axillary surgery. Primary tumor characteristics were similar between groups, although time to LR was shorter in the no-axillary-surgery group (median 3.4 versus 6.5 years, p<0.05). All patients in the axillary surgery group and 94% of patients in the no-axillary–surgery group had surgical excision of their LR, and the use of subsequent radiation and systemic therapy was similar between groups. At a median follow-up of 4.2 years from the time of LR, the rates of axillary failure, non-axillary failure, distant metastasis and death were low and did not differ between groups. Conclusions among breast cancer patients with LR and clinically negative nodes, our results question the value of axillary restaging but invite confirmation in larger patient cohorts. Since randomized trials support the value of systemic therapy for all patients with invasive LR, reoperative SLNB, although feasible, may not be necessary.

Patients with breast cancer may experience alterations in their tumor subtype after nCT. At our institution, this led to a change in adjuvant treatment in 100% of such patients. This implies that retesting receptor status of residual tumors after nCT should be routinely performed to tailor adjuvant therapy after nCT.