Correlation of C-myc and HER-2/neu amplification and expression with histopathologic variables in uterine corpus cancer

The BRD4 inhibitor JQ1 suppresses tumor growth by reducing c-Myc expression in endometrial cancer

Background

Endometrial cancer (EC) is the most common gynecological malignancy in developed countries. Efficacy of the bromodomain 4 (BRD4) inhibitor JQ1 has been reported for the treatment of various human cancers, but its potential impact on EC remains unclear. We therefore aimed to elucidate the function of BRD4 and the effects of JQ1 in EC in vivo and in vitro.

Methods

The mRNA expression of BRD4 was evaluated using datasets from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). BRD4 protein expression in EC tissues was measured using immunohistochemistry (IHC) assays. The effects of JQ1 on EC were determined by using MTT and colony formation assays, flow cytometry and xenograft mouse models. The underlying mechanism was also examined by western blot and small interfering RNA (siRNA) transfection.

Results

BRD4 was overexpressed in EC tissues, and the level of BRD4 expression was strongly related to poor prognosis. The BRD4-specific inhibitor JQ1 suppressed cell proliferation and colony formation and triggered cell apoptosis, cell cycle arrest, and changes in the expression of proteins in related signaling pathways. Moreover, JQ1 decreased the protein expression of BRD4 and c-Myc, and knockdown of BRD4 or c-Myc reduced the viability of EC cells. Intraperitoneal administration of JQ1 (50 mg/kg) significantly suppressed the tumorigenicity of EC cells in a xenograft mouse model.

Conclusion

Our results demonstrate that BRD4 is a potential marker of EC and that the BRD4 inhibitor JQ1 is a promising chemotherapeutic agent for the treatment of EC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03545-x.

KAT6A amplifications are associated with shorter progression-free survival and overall survival in patients with endometrial serous carcinoma

Somatic copy number alterations (CNA) are common in endometrial serous carcinoma (ESC). We used the Tumor Cancer Genome Atlas Pan Cancer dataset (TCGA Pan Can) to explore the impact of somatic CNA and gene expression levels (mRNA) of cancer-related genes in ESC. Results were correlated with clinico-pathologic parameters such as age of onset, disease stage, progression-free survival (PFS) and overall survival (OS) (n = 108). 1,449 genes with recurrent somatic CNA were identified, observed in 10% or more tumor samples. Somatic CNA and mRNA expression levels were highly correlated (r> = 0.6) for 383 genes. Among these, 45 genes were classified in the Tier 1 category of Cancer Genome Census-Catalogue of Somatic Mutations in Cancer. Eighteen of 45 Tier 1 genes had highly correlated somatic CNA and mRNA expression levels including ARNT, PIK3CA, TBLXR1, ASXL1, EIF4A2, HOOK3, IKBKB, KAT6A, TCEA1, KAT6B, ERBB2, BRD4, KEAP1, PRKACA, DNM2, SMARCA4, AKT2, SS18L1. Our results are in agreement with previously reported somatic CNA for ERBB2, BRD4 and PIK3C in ESC. In addition, AKT2 (p = 0.002) and KAT6A (p = 0.015) amplifications were more frequent in tumor samples from younger patients (<60), and CEBPA (p = 0.028) and MYC (p = 0.023) amplifications were more common with advanced (stage III and IV) disease stage. Patients with tumors carrying KAT6A and MYC amplifications had shorter PFS and OS. The hazard ratio (HR) of KAT6A was 2.82 [95 CI 1.12-7.07] for PFS and 3.87 [95 CI 1.28-11.68] for OS. The HR of MYC was 2.25 [95 CI 1.05-4.81] and 2.62[95 CI 1.07-6.41] for PFS and OS, respectively.

Ornithine decarboxylase as a therapeutic target for endometrial cancer

Ornithine Decarboxylase (ODC) a key enzyme in polyamine biosynthesis is often overexpressed in cancers and contributes to polyamine-induced cell proliferation. We noted ubiquitous expression of ODC1 in our published endometrial cancer gene array data and confirmed this in the cancer genome atlas (TCGA) with highest expression in non-endometrioid, high grade, and copy number high cancers, which have the worst clinical outcomes. ODC1 expression was associated with worse overall survival and increased recurrence in three endometrial cancer gene expression datasets. Importantly, we confirmed these findings using quantitative real-time polymerase chain reaction (qRT-PCR) in a validation cohort of 60 endometrial cancers and found that endometrial cancers with elevated ODC1 had significantly shorter recurrence-free intervals (KM log-rank p = 0.0312, Wald test p = 5.59e-05). Difluoromethylornithine (DFMO) a specific inhibitor of ODC significantly reduced cell proliferation, cell viability, and colony formation in cell line models derived from undifferentiated, endometrioid, serous, carcinosarcoma (mixed mesodermal tumor; MMT) and clear cell endometrial cancers. DFMO also significantly reduced human endometrial cancer ACI-98 tumor burden in mice compared to controls (p = 0.0023). ODC-regulated polyamines (putrescine [Put] and/or spermidine [Spd]) known activators of cell proliferation were strongly decreased in response to DFMO, in both tumor tissue ([Put] (p = 0.0006), [Spd] (p<0.0001)) and blood plasma ([Put] (p<0.0001), [Spd] (p = 0.0049)) of treated mice. Our study indicates that some endometrial cancers appear particularly sensitive to DFMO and that the polyamine pathway in endometrial cancers in general and specifically those most likely to suffer adverse clinical outcomes could be targeted for effective treatment, chemoprevention or chemoprevention of recurrence.

Correlation Between the Clinical Parameters and Tissue Phenotype in Patients Affected by Deep-Infiltrating Endometriosis

The current study aimed to identify and validate an applicable immunohistochemistry panel including Ki-67, c-MYC, estrogen receptor-α (ER-α), and progesterone receptor isoforms A/B (PR-A/B) in correlation with clinicopathological parameters in patients affected by deep infiltrating endometriosis. Tissue microarrays were prepared from a cohort of 113 patients. Phenotypic profile of the panel molecules was evaluated in glands and stroma in parallel with microvessels and stroma density measurements. Principal component analysis was performed on 8 immunohistochemical variables, 2 histological variables, and 8 subgroups of clinical parameters. The immunohistochemical profiling showed consistent Ki-67 immunostaining in 17.9% of the samples and c-MYC in 83.1%, while intense ER-α immunoreactivity was detected in 84% of the samples and PR-A/B isoforms in 24.1% of them. The combination of clinical parameters and tissue phenotype allowed a stratification of endometriosis-affected patients. Such novel phenotypical and clinical correlation could be helpful in the future studies for a better stratification of the disease aiming at a personalized patient care.

An exploratory analysis of HER-2 amplification and overexpression in advanced endometrial carcinoma: a Gynecologic Oncology Group study

OBJECTIVES

To investigate the frequency and potential prognostic or predictive value of HER-2 amplification or overexpression in advanced and recurrent endometrial cancers.

METHODS

Immunohistochemical staining (IHC; DAKO Herceptest) and fluorescence in situ hybridization (FISH; Vysis Inc. PathVysion DNA Probe Kit) were performed on specimens collected on a randomized Gynecologic Oncology Group (GOG) protocol testing the addition of paclitaxel to doxorubicin/cisplatin.

RESULTS

HER-2 overexpression (either 2+ (moderate) or 3+ (strong) immunostaining) and HER-2 gene amplification (a ratio of HER-2 copies to chromosome 17 (CEP17) copies > or = 2) were detected in 44% (104 of 234; 58 were 2+ and 46 were 3+) and 12% (21 of 182) of specimens, respectively. There was a significant increased frequency of overexpression in serous tumors vs. all others (23 of 38, 61% vs. 81 of 196, 41%, respectively, P=0.03). HER-2 amplification also appeared to be more common in serous tumors, but results were not significant (6 of 28, 21% vs. 15 of 141, 11%, P=0.12). There was a significant association between grade and HER-2 amplification among nonserous tumors, with grades 1, 2, and 3 cancers demonstrating 3%, 2%, and 21% amplification, respectively (P=0.003). Neither overexpression nor amplification predicted overall survival (OS) after adjusting for treatment and performance status.

CONCLUSIONS

HER-2 amplification was more common in high grade tumors with a trend to being more common in serous tumors. There was no clear evidence for a survival difference or a difference in benefit from the addition of paclitaxel for women with HER-2 amplified or overexpressed tumors; however, power to detect clinically meaningful differences was low.

Molecular targets in gynaecological cancers

The application of high throughput expression profiling and other advanced molecular biology laboratory techniques has revolutionised the management of cancers and is gaining attention in the field of gynaecological cancers. Such new approaches may help to improve our understanding of carcinogenesis and facilitate screening and early detection of gynaecological cancers and their precursors. Individualised prediction of patients' responses to therapy and design of personalised molecular targeted therapy is also possible. The studies of various molecular targets involved in the various signal pathways related to carcinogenesis are particularly relevant to such applications. At the moment, the application of detection and genotyping of human papillomavirus in management of cervical cancer is one of the most well established appliances of molecular targets in gynaecological cancers. Methylation, telomerase and clonality studies are also potentially useful, especially in assisting diagnosis of difficult clinical scenarios. This post-genomic era of clinical medicine will continue to make a significant impact in routine pathology practice. The contribution of pathologists is indispensable in analysis involving tissue microarray. On the other hand, both pathologists and bedside clinicians should be aware of the limitation of these molecular targets. Interpretation must be integrated with clinical and histopathological context to avoid misleading judgement. The importance of quality assurance of all such molecular techniques and their ethical implications cannot be over-emphasised.

Immunohistochemical analysis of c-myc, c-jun and estrogen receptor in normal, hyperplastic and neoplastic endometrium

To evaluate the role of c-jun and c-myc proto-oncogenes in normal, hyperplastic and neoplastic endometrium in relation to estrogen receptor (ER) status and to investigate whether these genes can be related to other histopathological features of endometrial carcinoma, 32 endometrial carcinomas, 38 endometrial hyperplasias and 22 cyclic endometria (10 proliferative and 12 secretory) were evaluated histologically. Endometrial hyperplasia cases were classified as simple and complex hyperplasia without atypia, and atypical hyperplasia. Endometrial carcinoma cases were subtyped according to the International Society of Gynecological Pathologists. Modified FIGO system was used for both grading and staging. Immunohistochemical examination was performed using antibodies to ER-alpha, c-myc and c-jun with streptavidin-biotin-peroxidase technique. The mean percentage of ER-alpha positive cells changed cyclically during the menstrual cycle, and it was the highest (96%) and the lowest (31.6%) in proliferative and carcinomatous endometrium, respectively. There was a statistically significant difference between proliferative and secretory phases and proliferative and carcinomatous endometrium in relation to ER-alpha staining (p<0.05). There was also a statistically significant difference with respect to ERalpha reactivity between secretory phase and each hyperplastic group, as well as between the carcinoma group and each hyperplastic group (p<0.05). Although not significant, the mean percentage of c-myc expressing cells in the carcinoma group was higher (15.3%) than that of proliferative phase and hyperplastic groups. The mean percentage of c-jun positive cells in proliferative endometrium was slightly higher than in secretory endometrium, and it was the highest in atypical hyperplastic endometrium (28.3%), but there was no statistically significant difference between the groups. In carcinoma cases, a positive correlation was observed between c-jun positivity and tumor grade (p=0.027, r=0.3908), but such a correlation with c-myc was not found. A positive correlation was detected between ER-alpha and c-myc expression (p=0.038, r=0.3686). A progressive loss of ER seems to be correlated with increasing malignant transformation. C-myc expression might play a role in the development of endometrial carcinoma via ER. The association between c-jun and ER appears to be lost in endometrial carcinoma. The relationship between c-myc, c-jun and ER appears to be altered in endometrial carcinoma compared to that of menstrual endometrium.

Nuclear and cytoplasmic c-myc staining in endometrial carcinoma and their relationship to survival

OBJECTIVE

The role of the c-myc proto-oncogene in genomic instability is just becoming more fully understood. However, its role in endometrial cancer is essentially unknown. The objective of this study was to determine the relationship between cytoplasmic and nuclear c-myc staining, DNA index, and survival in patients with endometrial carcinoma.

METHODS

One hundred and twenty-one patients with endometrial carcinoma were studied. Image analysis was used to determine DNA index. In addition to cytoplasmic and nuclear c-myc staining and DNA index, histologic type, stage, grade, depth of invasion, lymphvascular space invasion, and peritoneal cytology were evaluated as prognostic indicators. Univariate and multivariate analyses were performed.

RESULTS

One hundred and twenty-one patients were followed for over 5 years. c-myc cytoplasmic staining was present in 75.2% of the patients' tumors, and nuclear staining was present in 66.9% (P = 0.99). DNA index was significantly higher in patients with nuclear c-myc staining and no cytoplasmic staining (DNA index 1.38) as compared to those patients whose tumors displayed cytoplasmic c-myc staining but no nuclear c-myc staining (1.18) (P = 0.016). Patients whose tumors stained positively for nuclear c-myc and negatively for cytoplasmic c-myc had significantly worse survival by Kaplan-Meier analysis (P < 0.0001). Seventeen patients died during the follow-up period of this study. By multivariate analysis, positive cytoplasmic c-myc staining with negative nuclear staining (P = 0.0076), negative cytoplasmic c-myc staining with positive nuclear staining (P = 0.011) and FIGO stage (P < 0.0001) were shown to be independent prognostic indicators predictive of survival.

CONCLUSION

Nuclear and cytoplasmic c-myc staining, as well as FIGO stage, when assessed by multivariate analysis, were demonstrated to be important factors in predicting survival in the 121 patients in this study. While increasing FIGO stage was prognostic of decreased survival, the specific location of c-myc staining was also associated with prognosis. The expression of the c-myc protein is related to survival in patients with adenocarcinoma of the endometrium.

The coexistence of ERBB2, INT2, and CMYC oncogene amplifications and PTEN gene mutations in endometrial carcinoma

PURPOSE

To evaluate the frequency of ERBB2, INT2 and CMYC oncogene amplifications and their coexistence with PTEN gene mutations in endometrial carcinomas.

METHODS

In 54 endometrial carcinomas amplification of ERBB2, INT2 and CMYC was determined using differential polymerase chain reaction (dPCR), and mutations in all exons of PTEN were investigated by PCR-SSCP and direct sequencing methods. Results were correlated with clinicopathological features of tumors.

RESULTS

In 31 out of 54 endometrial carcinomas (57.4%) genetic defects were found within the examined genes. Of all identified defects, mutations in PTEN and the amplification of CMYC were most frequent (26/54-48.1% and 10/54-18.5%, respectively). INT2 was amplified in 5.6% (3/54) of cases. In no case did we find ERBB2 amplification. In 77.4% (24/31) of cases only one gene was damaged. Of these, 20 cases showed only PTEN mutations, three cases only CMYC, and one case only INT2 amplification. In another seven out of 31 tumors (22.5%) defects in two or three genes coexisted simultaneously: PTEN and CMYC in five cases, CMYC and INT2 in one case, and PTEN, CMYC, and INT2 in one case. We found a number of interesting relations between the location of mutations within the PTEN sequence and the presence (+) or lack (-) of CMYC amplification. In the PTEN+CMYC- tumors the PTEN mutations were most frequent in exons 1-5, and less frequent in exons 7-8 (66.7% and 33.3%, respectively). In contrast, in the PTEN+CMYC+ carcinomas the PTEN mutations were found mainly in exons 7-8 (85.7%). PTEN mutations were equally frequent in both early and more advanced endometrial carcinomas. The CMYC amplification, however, was more frequent in advanced as compared to early tumors, although this difference did not reach statistical significance.

CONCLUSIONS

Our data suggest that differences in the presence of genetic defects may reflect the different molecular pathways of endometrial carcinogenesis. These data also suggest that location of intragenic PTEN mutations and their coexistence with the CMYC amplification may play a crucial part in the development of various subtypes of endometrial carcinoma, but this preliminary suggestion requires further research.

Genome-wide-array-based comparative genomic hybridization reveals genetic homogeneity and frequent copy number increases encompassing CCNE1 in fallopian tube carcinoma

Fallopian tube carcinoma (FTC) is a rare, poorly studied and aggressive cancer, associated with poor survival. Since tumorigenesis is related to the acquisition of genetic changes, we used genome-wide array comparative genomic hybridization to analyse copy number aberrations occurring in FTC in order to obtain a better understanding of FTC carcinogenesis and to identify prognostic events and targets for therapy. We used arrays of 2464 genomic clones, providing approximately 1.4 Mb resolution across the genome to map genomic DNA copy number aberrations quantitatively from 14 FTC onto the human genome sequence. All tumors showed a high frequency of copy number aberrations with recurrent gains on 3q, 6p, 7q, 8q, 12p, 17q, 19 and 20q, and losses involving chromosomes 4, 5q, 8p, 16q, 17p, 18q and X. Recurrent regions of amplification included 1p34, 8p11-q11, 8q24, 12p, 17p13, 17q12-q21, 19p13, 19q12-q13 and 19q13. Candidate, known oncogenes mapping to these amplicons included CMYC (8q24), CCNE1 (19q12-q21) and AKT2 (19q13), whereas PIK3CA and KRAS, previously suggested to be candidate driver genes for amplification, mapped outside copy number maxima on 3q and 12p, respectively. The FTC were remarkably homogeneous, with some recurrent aberrations occurring in more than 70% of samples, which suggests a stereotyped pattern of tumor evolution.

Expression of nm23 in normal, hyperplastic and neoplastic endometrial tissues

This study evaluated the expression of nm23 in curettage specimens from 63 cases of normal, hyperplastic and neoplastic endometrial tissues by immunohistochemistry. The histological diagnoses were as follows: normal proliferative (N = 5) or secretory (N = 5), simple hyperplasia (N = 11), complex hyperplasia (N = 9), atypical hyperplasia (N = 8) and adenocarcinoma (N = 25), consisting of endometrioid adenocarcinoma (N = 15), clear cell (N = 7) and serous papillary adenocarcinoma (N = 3). There was no immunostaining for nm23 protein in the 10 cases of normal endometria and in the 28 cases of endometrial hyperplasia. In contrast, 52% of the adenocarcinomas displayed a cytoplasmic staining pattern which was moderate to strong. This difference was statistically significant (p < 0.0001, chi-square test). nm23 expression in curettage specimens had no predictive value for determining the FIGO stage in the hysterectomy specimens (p = 0.2709, chi-square test). No significant difference for nm23 immunoreactivity was found between the histologic subtypes of endometrial adenocarcinoma (endometrioid versus serous papillary and clear cell, p = 0.1413, chi-square test). In this study, there was no immunostaining of normal endometria or of endometrial hyperplasia (including atypical endometrial hyperplasia) to support the hypothesis that expression of the nm23 gene product is related to the development of endometrial adenocarcinoma. In contrast, nm23 expression was upregulated in many cases of endometrial adenocarcinomas irrespective of the histologic subtype.

Fluorescence in situ hybridization analysis of HER-2/neu, c-myc, and p53 in endometrial cancer

Our objective was to evaluate the association between HER-2/neu, c-myc, p53, and clinicopathologic variables in endometrial cancer using fluorescence in situ hybridization (FISH) cytogenetic analysis. FISH analysis for HER-2/neu, c-myc, and p53 was performed on 47 endometrial cancer specimens. Amplification of HER-2/neu was seen in 4/47 (8.5%) cases and amplification of c-myc was seen in 7 of 47 (15%) cases; neither was associated with adverse clinicopathologic variables or survival. Deletion of p53 was seen in 31/47 (66%) cases and was associated with poor histologic grade (P = 0.008). There was no impact of genetic alterations on overall survival or disease-free interval. Grade 3 tumor was associated with poor overall survival (P = 0.032). This study found that p53 deletion is a common genetic alteration in endometrial cancer and is associated with poor-grade tumors.

Value of glutathione S-transferase pi and the oncogene products c-Jun, c-Fos, c-H-Ras, and c-Myc as a prognostic indicator in endometrial carcinomas

OBJECTIVE

To examine the relationship between the expressions of glutathione S-transferase pi (GST-pi) and four oncogene products, c-Jun, c-Fos, c-H-Ras, and c-Myc, and clinicopathological prognostic factors and patients' prognosis in endometrial carcinomas, and to assess their prognostic value in endometrial carcinomas.

METHODS

Specimens of endometrial carcinoma obtained from 63 patients were investigated immunohistochemically using respective specific antibodies.

RESULTS

The overall positive rates in 63 carcinoma specimens were 34.9% for GST-pi, 44.4% for c-Jun, 34.9% for c-Fos, 47.6% for c-H-Ras, and 54.0% for c-Myc. Multivariate analysis revealed that GST-pi expression correlated independently with paraaortic lymph node (PAN) metastasis, and c-Jun expression was independently related to pelvic lymph node (PLN) and PAN metastasis. The prognosis of patients with a GST-pi-positive tumor was significantly poorer than that of those with a GST-pi-negative tumor (P < 0.05). The patients with c-Jun-positive tumor also had a significantly worse prognosis than those with c-Jun-negative tumor (P < 0.05). No significant relationship between the expressions of the remaining three oncogene products, c-Fos, c-H-Ras, and c-Myc, and the examined prognostic factors and clinical outcome was apparent.

CONCLUSION

These results suggest that the expressions of GST-pi and c-Jun may reflect the metastatic potential of endometrial carcinomas and that their expressions of endometrial carcinoma may be useful as a prognostic indicator for predictive testing.

Immunohistochemically detected HER-2/neu-expression and prognosis in endometrial carcinoma

Expression of the HER-2/neu proto-oncogene product was looked for immunohistochemically in 222 endometrial carcinomas in a retrospective follow-up study. The intensity of protein expression was correlated with patient survival. Median follow-up time was 4.8 years. In 109 (49%) of 222 endometrial carcinomas there was aberrant expression of HER-2/neu. HER-2/neu-expression did not correlate with p53-expression and proliferation rate, as determined immunohistochemically by the monoclonal antibody Ki-S1. In univariate statistical analysis aberrant HER-2/neu expression was not predictive of adjusted survival (p = 0.18) and of disease-free survival (p = 0.42). In multivariate analysis HER-2/neu-expression was not found to be an independent prognosticator (p = 0.099) as compared to FIGO-stage (p = 0.0001), histologic grade (p = 0.00099) and proliferation rate (p = 0.0013). Therefore immunohistochemically detected expression of HER-2/neu seems not to be a clinical prognosticator in endometrial cancer.

Epidermal growth factor receptor and c-erbB-2 oncoprotein expression in female genital tract carcinosarcomas (malignant mixed müllerian tumors). Clinicopathologic study of 82 cases

BACKGROUND

Epidermal growth factor receptor (EGFR) and c-erbB-2 (also known as HER-2/neu) oncoprotein (p185erbB-2) are members of the subfamily of tyrosine kinase, transmembrane receptors often implicated in human carcinogenesis. We hypothesize that expression of EGFR and p185erbB-2 adds useful prognostic and histogenetic information regarding female genital tract carcinosarcomas (FGTCSs).

METHODS

Paraffin sections from 82 FGTCS (61 endometrium, 14 ovary, 5 cervix, and 2 fallopian tube), 56% of which exhibited heterologous elements, were stained using anti-EGFR (clone 31G7, Triton Diagnostics, Alameda, CA) and anti-p185erbB-2 (clone CB11, Novocastra Labs, UK).

RESULTS

EGFR reactivity was present in 11 (13.4%) FGTCSs (55% carcinomatous component [CC] only, 18% sarcomatous component [SC] only, and 27% in both). EGFR was associated with adenosquamous histology of the CC (P < 0.05) and heterologous rhabdomyosarcomatous differentiation in the SC (P < 0.05); no other histopathologic features were correlated. p185erbB-2 reactivity was present in 79 (87.8% strong [S], 78% membrane [M], and 8.5% weak) FGTCSs (1% CC only, 0% SC only, and 99% in both). p185erbB-2 did not correlate with histopathologic features or EGFR. Seventy-seven patients had clinical follow-up for longer than 12 months. Approximately 49.3% and 72.3% of patients had recurrent disease by 12 and 80 months, respectively; all but 1 were dead from disease. 27% of patients were disease free after 15 to 307 months (median, 77 months; mean, 92 months). EGFR, but not p185erbB-2 expression predicted disease recurrence (P < 0.05). Recurrent disease was associated with Stage greater than I (P < 0.0001), vascular space invasion in resection specimens (P < 0.01), and deep myometrial invasion in hysterectomies (P < 0.05). EGFR was associated with Stage greater than I and did not help predict recurrence in good prognosis groups.

CONCLUSIONS

p185erbB-2 overexpression in both CC and SC of FGTCS suggests a common carcinogenic mechanism for both components and supports the conversion-histogenesis hypothesis implicating a dominant role for the CC with the SC arising as a metaplastic change from the CC. EGFR may be expressed in either component and indicates aggressive biologic behavior; however, its prognostic utility is limited by its low predictive value for recurrence (40.3%), inability to foretell recurrence in good prognosis groups, and dependence on stage. High frequency of overexpression and dismal prognosis make FGTCS patients good candidates for trials of therapeutic strategies involving the p185erbB-2 receptor manipulations.

Molecular basis of endometrial cancer

BACKGROUND

Most human cancers are thought to arise from alterations in oncogenes and tumor suppressor genes.

METHODS

Molecular techniques have been used to identify specific genetic alterations in endometrial cancers.

RESULTS

Overexpression of the HER-2/neu oncogene occurs in 10% of endometrial cancers and correlates with poor survival. Alterations in other receptor tyrosine kinases (c-fms and epidermal growth factor receptor) also occur in some cases. The c-myc oncogene, which encodes a nuclear transcription factor, also may be overexpressed in some invasive cancers. Mutations in the K-ras oncogene occur in 10% and in 20-30% of American and Japanese endometrial cancers, respectively. K-ras mutations also have been observed in endometrial hyperplasias, and this may represent an early event in the development of some cancers. Mutation of the p53 tumor suppressor gene, with resultant overexpression of mutant p53 protein, occurs in 20% of endometrial adenocarcinomas. Overexpression of p53 is associated with advanced stage and poor survival. Because p53 mutations do not occur frequently in endometrial hyperplasias, this may be a relatively late event in endometrial carcinogenesis. Recent studies have shown that mutations occur in microsatellite sequences in some endometrial cancers. Because microsatellite instability in hereditary nonpolyposis colon cancer has been found to be caused by mutations in DNA repair genes, similar mutations are being sought in endometrial cancers.

CONCLUSIONS

Although several molecular alterations have been identified, the molecular pathogenesis of endometrial cancer remains poorly understood.

Biomarkers in the endometrium

A number of oncogenes and tumor suppressor genes that may serves as surrogate biomarkers of transformation are altered during the process of endometrial carcinogenesis. Overexpression of HER-2/neu occurs in 10% of endometrial adenocarcinomas and correlates with intraperitoneal spread of disease and poor survival. The c-myc oncogene is amplified in 10% of cases. Point mutations in codon 12 of the K-ras oncogene have been reported to occur in 10-20% of endometrial cancers. K-ras mutations also have been noted in some endometrial hyperplasias, which may represent an early event in the development of some endometrial cancers. Mutation of the p53 tumor suppressor gene, with resultant overexpression of mutant p53 protein, occurs in 20% of endometrial adenocarcinomas. Overexpression of p53 is associated with advanced stage and poor survival. Because p53 mutations have not been observed in endometrial hyperplasias, this is thought to be a relatively late event in endometrial carcinogenesis. Microsatellite instability has also been noted in approximately 15% of sporadic endometrial cancers, but mutations in DNA repair genes have not yet been reported. Chemoprevention trials in endometrial cancer may be feasible due to the existence of a premalignant lesion and surrogate biomarkers.