Clinicopathologic and immunohistochemical features and microsatellite status of endometrial cancer of the uterine isthmus

The significance of lower uterine segment involvement in endometrial cancer

BACKGROUND

Limited data suggests lower uterine segment involvement (LUSI) in endometrial cancer may be associated with other poor prognostic factors. We assessed the unclear impact of LUSI on prognosis in endometrial cancer.

METHOD

ology: A revision of pathological samples following surgical staging between the years 2002-2022 was performed and clinical data collected from patients' records. Characteristics and outcomes of women with and without LUSI were compared and analysed. Kaplan Meyer survival curves compared overall survival (OS) and progression-free survival (PFS).

RESULTS

429 women were included, of which 45 (10.5%) had LUSI. No differences were found between the groups regarding demographic or clinical characteristics. LUSI was significantly associated with lympho-vascular space invasion (40% vs. 22% p = 0.01), lymph node involvement (6.4% vs. 9.1%, p = 0.05), shorter PFS (4 vs. 5.5 years, p = 0.01) and OS (5.6 vs. 11.5 years, p = 0.03). Multivariate analysis showed higher hazard ratios for OS and PFS (1.55 95%CI 0.79-3.04 and 1.29 95%CI 0.66-2.53, respectively) but these were insignificant even in a sub-analysis of endometrioid histology (1.76 95%CI 0.89-3.46 and 1.35 95%CI 0.69-2.65, respectively). A trend towards decreased PFS and OS was demonstrated in the Kaplan Meyer survival curves for all cases (log rank test p = 0.5 and 0.29 respectively), endometrioid histology (log rank test p = 0.06 and 0.51 respectively) and early-stage disease (log rank test p = 0.63 and 0.3 respectively).

CONCLUSION

LUSI may be related to poorer outcome of endometrial cancer and may represent an additional factor to consider when contemplating adjuvant treatment, especially in endometrioid-type and early-stage disease.

Clinicopathologic features and BRCA mutations in primary fallopian tube cancer in Japanese women

Objective

The present study aimed to clarify the clinicopathological features, including the level of p53 protein expression and BRCA mutations, of primary fallopian tube cancer (PFTC) in Japanese women.

Methods

A multicenter clinical survey was conducted at three Japanese institutions. Clinical data in patients with PFTC between 1998 and 2016 were collected. Immunohistochemical staining of p53 and BRCA mutation analysis by exome sequence using paraffin-embedded surgical resected specimens were performed.

Results

A total of 40 patients with PFTC were enrolled in the study. The median age was 58 years (range: 38-78 years); 31 patients were menopausal. Thirty-four (85.0%) patients were diagnosed with serous adenocarcinoma (high grade, 33; low grade, 1). PFTC was classified into ampulla type, fimbriae type and undeterminable type by tumor-occupying lesion; ampulla type and fimbriae type occurred with the same frequency. Among 30 patients with high-grade serous adenocarcinoma, 6 patients showed germline mutations of BRCA1 (stop-gain 4 and frameshift deletion 2) and 2 patients showed germline mutation of BRCA2 (stop-gain 1 and frameshift deletion 1). However, only 1 patient had familial history of breast or ovarian cancer. Patients with BRCA mutations in the germline were frequently observed in ampulla type and FIGO stage I/II cancers, but no significant difference in the frequency of p53 overexpression and overall survival was observed.

Conclusions

Among Japanese patients with PFTC, 26.7% presented with BRCA mutations in the germline. Additionally, p53 was important for the carcinogenesis in fallopian tubes, independent of the specific BRCA mutation.

Clear cell carcinoma of the lower uterine segment: A case report

Uterine carcinoma of the lower uterine segment (LUS) is a rare tumor that accounts for 3–3.5% of cases of uterine malignant cancer. The tumor arises from the lower region of the uterine body through the upper region of the cervix. The present study reported a case of clear cell carcinoma that originated from the LUS. A 50-year-old woman visited a local hospital due to irregular vaginal bleeding. She was suspected to have a uterine tumor and was referred to Tachikawa Hospital (Tokyo, Japan). Transvaginal ultrasound and magnetic resonance imaging revealed a uterine tumor from the lower region of the uterine body through the upper region of the cervix. Endocervical curettage revealed clear cell carcinoma. Based on a diagnosis of clear cell carcinoma of the LUS, radical hysterectomy was performed with bilateral salpingo-oophorectomy, paraaortic lymph node dissection and omentectomy. Macroscopically, the tumor was limited to the lower region of the uterine body through the upper region of the cervix in the resected uterus. Histopathological findings indicated no tumors in the uterine corpus and uterine cervix, but clear cell carcinoma was observed in the LUS epithelium. At the 1-year follow-up, the patient remained free of local recurrence and metastasis. To the best of our knowledge, clear cell carcinoma of the LUS has not previously been reported. More cases are required to clarify the pathology.

Immunohistochemical characterization of endometrial carcinomas: endometrioid, serous and clear cell adenocarcinomas in association with genetic analysis

Developments in immunohistochemistry, which are closely linked with the advances in the analyses of genetic abnormalities and their associated molecular disorders as early and late histogenetic events, have contributed greatly to the improvement of pathological diagnostic confirmation and validation. Immunohistochemistry has also generated great benefit to the innovation of therapeutic strategies for various kinds of cancers. In this article, the three representative histological types of corpus cancer, namely, endometrioid adenocarcinoma, serous adenocarcinoma and clear cell adenocarcinoma, will be histologically approached in association with their immunohistochemical profiles as well as genetic disorders. First, the focus will be on 'Conventional/prototypic features,' followed by 'Controversy over conventional histological subclassification,' and subsequently 'Tumorigenesis and re-subclassification'.

Relationship of lower uterine segment cancer with Lynch syndrome: a novel case with an hMLH1 germline mutation

Lynch syndrome is a genetic disease that often develops in patients with endometrial cancer and is caused by abnormal DNA mismatch repair (MMR) genes. In the United States, it was recently reported that the prevalence of Lynch syndrome with an hMSH2 mutation in patients with endometrial cancer in the lower uterine segment (LUS) is much greater than that in patients with endometrial cancer, although no such reports have been published in Asia. In this study, we examined the correlation between endometrial cancer in LUS and abnormalities in MMR genes. We examined 625 patients, who were diagnosed with endometrial cancer and underwent a hysterectomy. Nine patients (1.4%) had cancer based on pathological confirmation of a tumor in the lower part of the uterus and no cancer in the upper part. These cases were compared with 27 cases of sporadic endometrial (non-LUS) cancer. The age and BMI of the patients with LUS cancer were significantly lower than those of the patients with non-LUS cancer. No differences were observed in the pathological characteristics. The microsatellite instability (MSI)-positive rates were similar. Immunohistochemistry showed a decreased expression of hMLH1 and hMSH6 in patients with LUS cancer. In contrast with earlier reports from the United States, hMSH2 was expressed in all the cases. Of the 2 patients with LUS cancer who exhibited high MSI, 1 patient showed abnormal methylation of hMLH1, while the other patient was diagnosed with Lynch syndrome with a mutation in the hMLH1 gene. This is the second report on the relationship of LUS cancer and Lynch syndrome, and the first to describe an Asian patient with LUS cancer with Lynch syndrome induced by an hMLH1 mutation.

Epigenetics and genetics in endometrial cancer: new carcinogenic mechanisms and relationship with clinical practice

Endometrial cancer is the seventh most common cancer worldwide among females. An increased incidence and a younger age of patients are also predicted to occur, and therefore elucidation of the pathological mechanisms is important. However, several aspects of the mechanism of carcinogenesis in the endometrium remain unclear. Associations with genetic mutations of cancer-related genes have been shown, but these do not provide a complete explanation. Therefore, epigenetic mechanisms have been examined. Silencing of genes by DNA hypermethylation, hereditary epimutation of DNA mismatch repair genes and regulation of gene expression by miRNAs may underlie carcinogenesis in endometrial cancer. New therapies include targeting epigenetic changes using histone deacetylase inhibitors. Some cases of endometrial cancer may also be hereditary. Thus, patients with Lynch syndrome which is a hereditary disease, have a higher risk for developing endometrial cancer than the general population. Identification of such disease-related genes may contribute to early detection and prevention of endometrial cancer.

Carcinoma of the Lower Uterine Segment (LUS): Clinicopathological Characteristics and Association with Lynch Syndrome

Endometrial cancer arises from the uterine body and fundus in many cases, but can also originate from the lower region of the uterine body through the upper region of the cervix. Such tumors are referred to as carcinoma of the lower uterine segment (LUS) or isthmus, and account for 3-6.3% of all cases of endometrial cancer. This relatively low incidence has permitted performance of only small-scale studies, but the clinical and pathological characteristics of carcinoma of the LUS in all these reports have differed from those of other endometrial cancers. Generally, endometrial cancer is classified into estrogen-dependent endometrioid adenocarcinoma (designated as type I), and non-endometrioid types that are less associated with estrogen and include poorly differentiated adenocarcinoma (type II). In some reports, carcinoma of the LUS has been found to have type II characteristics. Carcinoma of the LUS has also been associated with Lynch syndrome, a hereditary disease with frequent development of colorectal, endometrial, and ovarian cancers. Lynch syndrome is thought to be induced by mismatch repair gene mutation. The frequency of Lynch syndrome in cases of general endometrial cancer is 1-2%. In contrast, the frequency in patients with carcinoma of the LUS is much higher, with up to 29% of cases diagnosable with Lynch syndrome and a high frequency of hMSH2 mutation found in one study. This suggests that further investigation of the clinical and pathological characteristics of carcinoma of the LUS and the association with Lynch syndrome is required through performance of a large-scale survey.

Endometrial cancer implanted within a cesarean section scar

Several reports have documented adenocarcinoma arising from endometriotic implants within cesarean section (C-S) scars on the serosal surface of the uterus; however, endometrial cancer invading the C-S scar from the uterine cavity has not been described. We report a case of a grade 1 endometrioid adenocarcinoma 'drop' lesion invading a previous C-S scar with resultant cervical stromal invasion. Using both MR images and a thorough review of the pathology, the tumor at the C-S scar was determined to be an implant derived from a primary lesion at the uterine fundus. With increases in the incidence of both endometrial cancer and births by C-S, it is likely we will encounter more cases of iatrogenic implants of endometrial cancers in C-S scars.

DNA mismatch repair deficiency in sporadic colorectal cancer and Lynch syndrome

DNA mismatch repair (MMR) deficiency is one of the best understood forms of genetic instability in colorectal cancer (CRC), and is characterized by the loss of function of the MMR pathway. Failure to repair replication-associated errors due to a defective MMR system allows persistence of mismatch mutations all over the genome, but especially in regions of repetitive DNA known as microsatellites, giving rise to the phenomenon of microsatellite instability (MSI). A high frequency of instability at microsatellites (MSI-H) is the hallmark of the most common form of hereditary susceptibility to CRC, known as Lynch syndrome (LS) (previously known as hereditary non-polyposis colorectal cancer syndrome), but is also observed in approximately 15-20% of sporadic colonic cancers (and rarely in rectal cancers). Tumour analysis by both MMR protein immunohistochemistry and DNA testing for MSI is necessary to provide a comprehensive picture of molecular abnormality, for use in conjunction with family history data and other clinicopathological features, in order to distinguish LS from sporadic MMR-deficient CRC. Identification of the gene targets that become mutated in MMR-deficient tumours may explain, at least in part, some of the clinical, pathological and biological features of MSI-H CRCs and holds promise for developing novel therapeutics.

Immunohistochemical staining in the distinction between primary endometrial and endocervical adenocarcinomas: another viewpoint

Several studies have reported on the use of antibodies to monoclonal carcinoembryonic antigen (CEA) and vimentin (VIM) to distinguish between adenocarcinomas of endometrial (EM) and endocervical (EC) origin, with variably enthusiastic results. It is still unclear whether site of origin or pathway of differentiation (endometrioid [em] versus mucinous [m]) is more important in predicting immunohistochemical differences. In the present study, paraffin blocks from adenocarcinomas of known origin were retrieved and immunostained with monoclonal antibodies to VIM and CEA, as well as cytokeratins (CK) 4, 18, and 20, estrogen receptor (ER), and progesterone receptor (PR). Positivity was scored on a scale from 0 to 12, with emphasis on the pattern of differentiation (tumors with mixed patterns received separate scores for the em and m foci). Mean CEA scores for emEM (n = 27), mEM (17), mEC (10), and emEC (6) were 0.4, 0.9, 5.1, and 1.2, respectively. VIM scores were 6.9, 1.3, 0, 4.4; ER, 5.7, 4.2, 0, 1.6; PR, 7.6, 2.8, 0.1, 6.0; CK4, 9.2, 4.4, 8.5, 10.6; CK18, 6.4, 3.4, 5.5, 8.4; CK20, 0.7, 0, 0.5, 0.4. Both site and differentiation influenced these results, with the latter more important for VIM and PR, the former for ER, both for CEA (only mEC was frequently strongly positive), and neither for the CKs studied. No one stain or combination reliably distinguished endometrial from endocervical origin. The only immunostaining pattern that might identify a site of origin with more accuracy than hematoxylin & eosin evaluation alone is the combination of high VIM and ER scores in an endometrioid carcinoma, suggesting with about 95% accuracy in this series an endometrial origin of the tumor.