Malignant mixed Müllerian tumors of the uterus: a clinicopathologic, DNA flow cytometric, p53, and mdm-2 analysis of 44 cases

In vitro effects of FBXW7 mutation in serous endometrial cancer: Increased levels of potentially druggable proteins and sensitivity to SI-2 and dinaciclib

Serous endometrial cancers (ECs) are clinically aggressive tumors that frequently harbor somatic mutations in FBXW7 (F-box and WD repeat domain-containing 7). The FBXW7 tumor suppressor is part of a SCF (complex of SKP1, Cullin 1, F-box protein) ubiquitin ligase complex which controls the degradation of numerous substrates that, if not properly regulated, can contribute to the initiation or progression of tumorigenesis. Despite reports that up to 30% of serous ECs include somatic mutations in FBXW7, the molecular effects of mutated FBXW7 in ECs have not been determined. Here, we used transient transfection and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) editing in serous EC cell lines to interrogate the molecular effects of six recurrent FBXW7 mutations. We show that FBXW7 mutations lead to increased Cyclin E1, steroid receptor coactivator 3 (SRC-3), c-MYC, Rictor, glycogen synthase kinase 3 (GSK3), P70S6 kinase, and protein kinase B (AKT) phosphorylated protein levels in serous EC cells. Furthermore, we demonstrate that CRISPR-edited FBXW7-mutant ARK1 serous EC cells exhibit increased sensitivity to SI-2 (a SRC inhibitor) and dinaciclib (a cyclin dependent kinase (CDK) inhibitor) compared to parental ARK1 cells. Collectively, our findings reveal biochemical effects of FBXW7 mutations in the context of EC and provide in vitro evidence of sensitivity to targeted inhibitors.

Does a p53 "Wild-type" Immunophenotype Exclude a Diagnosis of Endometrial Serous Carcinoma?

An aberrant p53 immunophenotype may be identified in several histotypes of endometrial carcinoma, and is accordingly recognized to lack diagnostic specificity in and of itself. However, based on the high frequency with which p53 aberrations have historically been identified in endometrial serous carcinoma, a mutation-type immunophenotype is considered to be highly sensitive for the histotype. Using an illustrative case study and a review of the literature, we explore a relatively routine diagnostic question: whether the negative predictive value of a wild-type p53 immunophenotype for serous carcinoma is absolute, that is, whether a p53-wild type immunophenotype is absolutely incompatible with a diagnosis of serous carcinoma. The case is an advanced stage endometrial carcinoma that was reproducibly classified by pathologists from 3 institutions as serous carcinoma based on its morphologic features. By immunohistochemistry, the tumor was p53-wild type (DO-7 clone), diffusely positive for p16 (block positivity), and showed retained expression of PTEN, MSH2, MSH6, MLH1, and PMS2. Next generation sequencing showed that there indeed was an underlying mutation in TP53 (D393fs*78, R213*). The tumor was microsatellite stable, had a low mutational burden (4 mutations per MB), and displayed no mutations in the exonuclease domain of DNA polymerase epsilon (POLE) gene. Other genomic alterations included RB1 mutation (R46fs*19), amplifications in MYST3 and CRKL, and ARID1A deletion (splice site 5125-94_5138del108). A review of the recent literature identified 5 studies in which a total of 259 cases of serous carcinoma were whole-exome sequenced. The average TP53 mutational rate in endometrial serous carcinoma was only 75% (range, 60 to 88). A total of 12 (33%) of 36 immunohistochemical studies reported a p53-aberrant rate of <80% in endometrial serous carcinoma. We discuss in detail several potential explanations that may underlie the scenario of serous carcinoma-like morphology combined with p53-wild-type immunophenotype, including analytic limitations, a nonserous histotype displaying morphologic mimicry of serous carcinoma, and true biological phenomena (including the possibility of a TP53-independent pathway of endometrial serous carcinogenesis). Ultimately, our central thematic question is provisionally answered in the negative. At present, the available data would not support a categorical conclusion that a p53 alteration is a necessary and obligate component in the genesis and/or diagnosis of endometrial serous carcinoma. On the basis of their collective experience, the authors proffer some recommendations on the use of p53 immunohistochemistry in the histotyping of endometrial carcinomas.

Establishment of primary xenograft model from newly characterized patient extrauterine carcinosarcoma

BACKGROUND AND OBJECTIVE

The aim of this study was to characterize primary cells from extrauterine carcinosarcoma (CS) and to establish a primary CS xenograft mouse model.

METHODS

Primary cells were isolated from a patient with CS and cultured in vitro. Primary CS cells were verified for their ability to consecutively generate tumorigenesis in NOD/SCID mice. The properties of xenograft tumor and explants cells were investigated by immunohistochemistry, cytogenetic, and FACS analysis. Anticancer drug susceptibility of primary CS was analyzed using CCK-8.

RESULTS

Primary CS cells greater than 27 passages in vitro showed an ability of a series of xenograft tumorigenesis in vivo having the same marker expression and cytogenetic character as that of original tumor. In addition, explants of xenograft tumors retained their original characteristics in the in vitro culture system. Finally, the analysis of the susceptibility to anticancer drug revealed that primary CS cells were susceptible to both doxorubicin and nilotinib, which are tyrosine kinase inhibitors.

CONCLUSIONS

The primary CS cells and the primary CS xenograft tumorigenesis introduce a new therapeutic model for targeting cancer and also explore a deeper understanding of generation of the tumor itself.

Malignant mixed Mullerian tumors of the uterus: histopathological evaluation of cell cycle and apoptotic regulatory proteins

Aim

The aim of our study was to evaluate survival outcomes in malignant mixed Mullerian tumors (MMMT) of the uterus with respect to the role of cell cycle and apoptotic regulatory proteins in the carcinomatous and sarcomatous components.

Methods

23 cases of uterine MMMT identified from the Saskatchewan Cancer Agency (1970-1999) were evaluated. Immunohistochemical expression of Bad, Mcl-1, bcl-x, bak, mdm2, bax, p16, p21, p53, p27, EMA, Bcl-2, Ki67 and PCNA was correlated with clinico-pathological data including survival outcomes.

Results

Histopathological examination confirmed malignant epithelial component with homologous (12 cases) and heterologous (11 cases) sarcomatous elements. P53 was strongly expressed (70-95%) in 15 cases and negative in 5 cases. The average survival in the p53+ve cases was 3.56 years as opposed to 8.94 years in p53-ve cases. Overexpression of p16 and Mcl-1 were observed in patients with longer survival outcomes (> 2 years). P16 and p21 were overexpressed in the carcinomatous and sarcomatous elements respectively. Cyclin-D1 was focally expressed only in the carcinomatous elements.

Conclusions

Our study supports that a) cell cycle and apoptotic regulatory protein dysregulation is an important pathway for tumorigenesis and b) p53 is an important immunoprognostic marker in MMMT of the uterus.

Loss of p16 in recurrent malignant mixed müllerian tumors of the uterus

Uterine malignant mixed müllerian tumors (MMMTs) are rare and highly aggressive malignancies with poor clinical prognoses. We examined for differences in the oncoprotein profiles of primary versus recurrent MMMTs. Five cases of recurrent uterine MMMT were examined by paraffin immunohistochemistry for the expression of p53, p16, P-cadherin, and Cerb-B2. P16, p53, and P-cadherin were each expressed in 100%, 80%, and 60% of the primary cases, respectively. Three cases expressed all three oncoproteins. All five cases were negative for Cerb-B2. No difference in antigen expression was seen in the epithelial versus sarcomatous components. Primary and recurrent tumors were concordant for p53, P-cadherin, and Cerb-B2. However, three cases of recurrent tumors were negative for p16 expression. P53, p16, and P-cadherin are common tumor suppressor genes expressed in uterine MMMT. Interestingly, p16 protein expression was lost in some cases of MMMTs when they recurred. This suggests that the oncoprotein and possibly genetic profile of p16 changes over time. We did not observe any difference in antigen expression between areas of epithelial or sarcomatous differentiation, which would support a single pluripotential malignant clone in the histogenesis of these tumors.

Molecular genetic changes in epithelial, stromal and mixed neoplasms of the endometrium

Endometrial carcinoma, endometrial stromal tumours and mixed malignant mesodermal tumours (MMMT) develop along distinctive molecular genetic pathways. Two distinctive types of endometrial carcinoma are distinguished, type I and type II, which develop along distinctive pathways and show different clinical behaviour and histological features. Type I carcinomas show endometrioid histology, are oestrogen-related and develop from atypical endometrial hyperplasia. The molecular tumorigenesis is comparable to colorectal carcinoma with a step-like progression and an accumulation of genetic alterations. Alterations of PTEN, K-Ras mutations and microsatellite instability are frequent and early events in type I carcinoma, whereas p53 mutations occur during progression to grade 3 carcinoma. Serous and clear cell carcinomas are considered type II carcinomas which are mostly unrelated to oestrogen. p53 mutations occur in almost all serous carcinomas and seem to occur early, leading to massive chromosomal instability and rapid tumour progression. Gene expression profiling has supported this dualistic model of endometrial carcinoma. There is evidence of molecular differences between serous and clear cell carcinomas as well as between endometrioid carcinomas with and without microsatellite instability. A dualistic model of tumorigenesis may be also suggested for endometrial stromal tumours. Endometrial stromal sarcomas (ESS; type I endometrial sarcoma) are oestrogen-related and seem to develop from endometrial stromal nodules (ESN). They are histologically and genetically distinct from undifferentiated endometrial sarcoma (UES) which seem to be mostly unrelated to oestrogen (type II endometrial sarcoma). ESS and ESN share the fusion gene JAZF1/JJAZ1 caused by a t(7;17)(p15;q21) translocation, whereas UES lacks a distinctive molecular alteration so far. In MMMT, which is considered a metaplastic carcinoma, p53 alteration occurs early, before clonal expansion and acquisition of genetic diversity during progression.

Endometrioid Carcinomas of the Uterine Corpus With Sex Cord-like Formations, Hyalinization, and Other Unusual Morphologic Features

We describe a series of unusual endometrioid carcinomas (ECs) of the uterine corpus characterized in significant part by cords of epithelioid cells, spindle cells, and a hyalinized stroma that sometimes formed osteoid. These features, particularly when prominent, produced an appearance strikingly different from that of conventional EC, sometimes resulting in problems in differential diagnosis, especially with a malignant mullerian mixed tumor (carcinosarcoma). The 31 patients ranged in age from 25 to 83 years (mean, 52 years). The proportion within each stage were as follows: stage Ia, 9.7%, stage Ib, 45.2%, stage Ic, 9.7%, stage IIb, 16.1%, stage IIIc 3.2%, and stage IV, 3.2%. In 4 patients (12.9%), staging information was not available. On microscopic examination, typical EC, which accounted for 10% to 90% of the tumor, was admixed in 90% of cases with cords of epithelioid or spindle cells within a hyalinized stroma. In 3 cases, the tumor contained cords of cells without a hyalinized stroma. Areas with a diffuse growth of fusiform cells suggesting endometrial stromal cells were also occasionally seen in minor amounts. Seventy percent of the tumors exhibited squamous differentiation, and in 50% of the tumors there was a background of endometrial hyperplasia. Two thirds of the tumors were grade 2 and the remainder were grade 1. Vascular space invasion was identified in seven tumors. On immunohistochemical analysis, the typical EC component was strongly positive for keratin, whereas the keratin staining was more focal and variable in the epithelial cells in the cords. Muscle markers (desmin, actin), CD10, and inhibin were negative in the latter. Overexpression of p53 was found in only 1 case. Eighty-three percent of the patients were alive with no evidence of disease on follow-up (range, 2-115 months; mean, 34.4 months). The clinical features, including a typically low stage and generally good prognosis, and histologic findings are different from those of malignant mullerian mixed tumors that are characterized by both high-grade carcinomatous and sarcomatous components and an aggressive clinical course. Confusion with other neoplasms, particularly those with sex cord-like growth, such as uterine tumors resembling ovarian sex cord tumors and epithelioid smooth muscle tumors, may also arise. We refer to tumors with the features described herein as "corded and hyalinized endometrioid carcinomas," a designation that reflects their two most striking and consistent features. Corded and hyalinized endometrioid carcinomas are yet another example of the protean phenotype of endometrioid adenocarcinomas of the female genital tract that has been appreciated only in the last two decades.

Expression of p27 and p53: comparative analysis of uterine carcinosarcoma and endometrial carcinoma

The aim of the study was to assess both p27 and p53 expression in the stromal and epithelial component of carcinosarcoma and to assess if their expression in the latter is different than in endometrial carcinoma. Immunohistochemical staining for p27 and p53 was performed on paraffin-embedded tissue blocks of 18 uterine specimens with carcinosarcoma and their expression assessed. Their expression in the epithelial element was also compared to that in 35 paraffin-embedded tissue blocks of endometrial endometrioid carcinoma. Reduced p27 expression was observed in a similarly high proportion of the stromal (77.8%) as well as of the epithelial component (66.7%) of carcinosarcoma. Although statistically not significant, the proportion of reduced p27 expression in endometrial carcinoma (85.7%) was higher than in the epithelial element of carcinosarcoma. The percentage of p53 overexpression in both elements of carcinosarcomas and in endometrial carcinomas was low and also similar (27.8 and 20.0%, respectively). Our results indicate that reduced p27 expression is common and p53 overexpression is infrequent in carcinosarcoma. Their similar rates of expression in the stromal and epithelial elements of the tumor support the contention of a monoclonal origin of carcinosarcoma. Unexpectedly, reduced p27 expression is more common in endometrial carcinoma than in the epithelial element of carcinosarcoma, in spite of the less favorable prognosticators and outcome in the latter. Further studies of p27 expression in carcinosarcoma are indicated to establish its clinical value in this aggressive malignancy.

Oncoprotein profiles of primary peritoneal malignant mixed mullerian tumors

Primary peritoneal malignant mixed müllerian tumors (MMMTs) are extremely rare and highly aggressive malignancies associated with poor clinical prognoses. We present a clinicopathologic review of three cases of this rare tumor by examining expression of selected oncoproteins by immunohistochemistry. Three consecutive cases of primary peritoneal MMMT were examined by paraffin immunohistochemistry for expression of p53, p16, BCL2, CerbB2, and classical cadherins E-cadherin, P-cadherin, and N-cadherin. All three cases expressed p16, but showed less consistent expression of other markers, with one case expressing p53 and one expressing BCL2. All cases were negative for membrane expression of Cerb-B2. The three classical cadherins were expressed in two cases with one case showing only weak N- and P-cadherin expression. No difference in antigen expression was seen in the epithelial compared to sarcomatous components. We conclude that p16 may be a common tumor suppressor gene expressed in peritoneal MMMT. P53 overexpression may be of lesser frequency in peritoneal MMMT compared to MMMT from the ovary and the uterus. We did not observe any difference in antigen expression between areas of epithelial or sarcomatous differentiation, which would support a single pluripotential malignant clone in the histogenesis of these tumors.

Malignant mixed mesodermal tumours: biology and clinical aspects

Mixed mesodermal tumours (MMTs) are relatively rare gynaecological tumours that have been poorly studied in clinical and molecular terms. They are chemosensitive (at least initially), although ultimately they have a poor prognosis. The biology of the tumour is fascinating in view of its composition of both epithelial and mesenchymal entities. We review herein the literature on the clinical and biological aspects of this malignancy.

Endometrial stromal sarcoma of the uterus: a clinicopathologic, DNA flow cytometric, p53, and mdm-2 analysis of 17 cases

Seventeen patients with endometrial stromal sarcoma (ESS) diagnosed between 1970 and 1996 were evaluated according to DNA ploidy, S-phase fraction (SPF), p53, and mdm-2 expression, as well as traditional clinical and pathologic prognostic factors, such as tumor stage, grade, and mitotic index. DNA flow cytometric analysis and immunohistochemical staining for p53 and mdm-2 were performed on paraffin-embedded archival tissue from the uterine tumors. Flow cytometric DNA histograms were obtained from 16 patients. The patients ranged in age from 41 to 78 years (median, 57 years). Seven (41%) patients were premenopausal. Thirteen low-grade ESS were DNA diploid and had a low SPF. Of these, two overexpressed p53, while only one was mdm-2 positive. Among the four high-grade ESS we found one (25%) DNA diploid tumor and three (75%) DNA aneuploid tumors. Two (50%) had an SPF greater than 10%, three (75%) were p53-positive, and two (50%) overexpressed mdm-2. During the observation period, nine (53%) patients (five with low-grade and four with high-grade tumors) died of disease. The 5-year survival rate for patients with low-grade ESS was 74%, while all four patients with high-grade ESS died of disease within 14 months of diagnosis. Using the log-rank test, we found a significant correlation between survival and tumor grade (P = 0.007), DNA ploidy (P = 0.026), SPF (P = 0.048), and FIGO surgical stage (P = 0.026). In conclusion, we found that tumor grade was a strong predictor of clinical outcome in ESS. In addition, a worse prognosis was found for those ESS patients with advanced disease, DNA aneuploidy, and a high SPF. There was no difference between the recurrent and nonrecurrent group of early stage (surgical stage I), low-grade ESS with regard to clinicopathological features, DNA ploidy, SPF, p53, and mdm-2 expression. All patients with high-grade ESS died of disease within 14 months of diagnosis. In contrast, only three of the 11 patients with early stage, low-grade ESS died of disease.

Adenosarcoma of the uterus: a clinicopathologic, DNA flow cytometric, p53 and mdm-2 analysis of 11 cases

Eleven patients with uterine adenosarcoma diagnosed between 1970 and 1995 were evaluated according to DNA ploidy, S-phase fraction, p53 and mdm-2 expression, and traditional clinical and pathological prognostic factors, such as tumor stage, grade and mitotic index. DNA flow cytometric analysis and immunohistochemical staining for p53 and mdm-2 were performed on paraffin-embedded archival tissue from the uterine tumors. The patients ranged in age from 41 to 90 years (median, 76 years). Only one patient was premenopausal at the time of diagnosis and five (45%) were nulliparous. One patient had received previous pelvic irradiation for anal squamous carcinoma. Six of the tumors (55%) were pure adenosarcoma and five (45%) were adenosarcoma with sarcomatous overgrowth. Nine patients had a stage I tumor and two had a stage II tumor. Among the six adenosarcomas we found three DNA diploid tumors, two DNA aneuploid tumors, and one DNA multiploid tumor. All adenosarcomas had an S-phase fraction less than 10%, except one that was not assessable. None was p53 positive and only one overexpressed mdm-2. All five adenosarcomas with sarcomatous overgrowth were DNA aneuploid, three (60%) had an S-phase fraction > 10%, two (40%) were p53 positive, and one (20%) overexpressed mdm-2. Five of the eleven patients suffered recurrences, and three (60%) of these developed lung metastases. During the observation period four (36%) patients (2 adenosarcomas and 2 adenosarcoma with sarcomatous overgrowth) died of disease, three patients died of intercurrent disease without recurrence, and the remaining four are alive with no evidence of disease. The overall five-year survival rate for all stages was 69%; for patients with AS it was 80%, while for those with adenosarcoma with sarcomatous overgrowth it was 50%. There were no variables which correlated with survival. In conclusion, we found hat the typical adenosarcoma had a tendency to be of low stage, have a lower mitotic rate and an S-phase fraction <10%. On the other hand, adenosarcomas with sarcomatous overgrowth were of high grade, had a high mitotic rate, and were DNA aneuploid with an S-phase fraction >10%. None of the variables studied correlated with survival. Tumors that were p53-positive or overexpressed mdm-2 did not behave worse than their negative counterpart. All patients who recurred with distant metastases died of disease.