High‐grade ovarian serous carcinoma exhibits significantly higher p16 expression than low‐grade serous carcinoma and serous borderline tumour

Recent literature has suggested a dual pathway of ovarian serous carcinogenesis, with most serous carcinomas falling into 1 of 2 categories, low grade and high grade. These are considered to represent 2 distinct tumor types with a different underlying pathogenesis and associated with different molecular events, clinical behavior, and prognosis. Low-grade serous carcinoma is thought to evolve in many instances from a preexisting serous borderline tumor and cystadenoma. Given the distinct pathogenesis and different molecular events, it is expected that the coexistence of low-grade and high-grade serous carcinoma would be rare or may even be mutually exclusive; moreover, there are very few reported examples in the literature. We report a series of 7 cases in patients aged 34 to 78 years in whom ovarian low-grade serous carcinoma (4 cases, including 3 with associated serous borderline tumor), serous borderline tumor (2 cases), or seromucinous borderline tumor (1 case) was associated with a high-grade carcinoma, either high-grade serous (5 cases) or undifferentiated carcinoma (2 cases). The low-grade and high-grade components coexisted in the original neoplasm in 4 cases, and the high-grade component was present only in recurrence in 3 cases. In both instances, the undifferentiated carcinoma had a focal rhabdoid morphology, and alternative primary sites of tumor were excluded by a combination of clinical, radiologic, and pathologic parameters. We illustrate that low-grade serous carcinoma or serous borderline tumor ("low-grade" serous neoplasms) may rarely be associated with, and probably give rise to, a high-grade carcinoma, either high-grade serous or undifferentiated carcinoma. The coexistence of a low-grade serous neoplasm and undifferentiated carcinoma can be regarded as a form of dedifferentiation. p53 was diffusely positive in 4 of 6 high-grade carcinomas, which raises the possibility that secondary Tp53 mutation is important in high-grade transformation in some of these cases. WT1 was negative in the 2 undifferentiated carcinomas, and PAX8 was positive in 1, suggesting that the latter marker is more useful in helping to confirm a Mullerian origin in dedifferentiated low-grade serous neoplasms.

Early detection and treatment of ovarian cancer: shifting from early stage to minimal volume of disease based on a new model of carcinogenesis

Backgroud: Ovarian carcinoma is the third most common malignancy in Indonesian women after breast and cervical cancer. Serous ovarian carcinoma is the most frequent subtype, divided into low-grade and high-grade types, each with distinct genetic and biological characteristics. Objective:This study aims to compare the clinicopathological features of high-grade and low-grade serous ovarian carcinoma. Methods: A retrospective cross-sectional study was conducted using 77 paraffin-embedded samples of serous ovarian carcinoma. Clinical and pathological data including age, body mass index (BMI), age at menarche, and parity were collected and analyzed using the chi-square test. Results: Patients aged >50 years accounted for most cases, with 64.3% presenting high-grade serous carcinoma (HGSC). Overweight/obesity was observed in 40.3% of cases. Early menarche (<13 years) was reported in 78%, and 42.7% were multiparous. No significant differences were found in clinical variables between HGSC and low-grade serous carcinoma (LGSC). Histopathologically, HGSC showed more pronounced cytologic atypia, necrosis, and metastasis. Conclusion: High-grade serous carcinoma demonstrates greater aggressiveness compared to its low-grade counterpart. Histopathological assessment plays a critical role in diagnosis, treatment decisions, and prognosis evaluation.

In this study, we evaluate a two-tier system for grading ovarian serous carcinoma. This system is based primarily on the assessment of nuclear atypia with the mitotic rate used as a secondary feature. The study included 50 cases of low-grade ovarian serous carcinoma and 50 cases of high-grade ovarian serous carcinoma retrieved from the files of the Department of Pathology at the University of Texas M. D. Anderson Cancer Center from a 28-year period. Cases assigned to the low-grade category were characterized by the presence of mild to moderate nuclear atypia. As a secondary feature, they tended to show up to 12 mitoses per 10 high power fields (HPFs), whereas those in the high-grade category had marked nuclear atypia and as a secondary feature more than 12 mitoses per 10 HPFs. For comparison, the tumors were also graded using the Shimizu/Silverberg and the FIGO grading systems. Patients in the low-grade ovarian serous carcinoma group ranged in age from 19 to 75 years (mean 41.7 years) while patients in the high-grade ovarian serous carcinoma group ranged in age from 27 to 76 years (mean 55 years). All of the cases except one were advanced FIGO stage. Using the Shimizu/Silverberg system, the low-grade ovarian serous carcinoma cases were distributed as follows: grade 1, 47 cases; grade 2, 3 cases. Using the FIGO grading system, 35 cases were grade 1 and 15 cases were grade 2. Regarding the high-grade ovarian serous carcinoma group using the Shimizu/Silverberg system, 14 of the cases were grade 2 and 36 cases were grade 3. Using the FIGO grading system, 1 case was grade 1, 38 cases were grade 2, and 11 cases were grade 3. Most of the patients in both groups were treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy and also received cisplatinum-based chemotherapy. On follow-up, 37 patients in the low-grade ovarian serous carcinoma group had died of disease at a median 4.2 years after diagnosis compared with 46 patients in the high-grade ovarian serous carcinoma group who died of disease at a median of 1.7 years. Eight patients in the low-grade ovarian serous carcinoma group and 4 patients in the high-grade ovarian serous carcinoma group were alive with disease at median follow-ups of 4.3 and 3.85 years, respectively. Four patients with low-grade serous carcinoma were alive without evidence of disease after a follow-up that ranged from 4.4 to 22.6 years (median 6.85 years), and one died of other causes 14 years after the diagnosis of her ovarian tumor. On multivariate analysis, residual tumor and tumor grade based on the M. D. Anderson two-tier system for grading ovarian serous carcinoma were found to be significant independent prognostic factors (P = 0.003 and 0.04, respectively). Of interest, 60% of the low-grade ovarian serous carcinomas in this study were associated with a serous neoplasm of low malignant potential, whereas this association was present in only 2% of the high-grade ovarian serous carcinomas. This finding could reflect a difference in the pathogenesis of ovarian serous carcinomas of different grades. In summary, there is usually a good correlation between the two-tier grading system herein presented and the Shimizu/Silverberg and the FIGO grading systems. Because this system is based on defined criteria that are easy to follow and because it involves only two diagnostic categories, it should provide better reproducibility in the grading of ovarian serous carcinoma. However, additional studies are required to validate these statements.

According to a tumor progression model, low-grade ovarian serous carcinomas may evolve from serous borderline tumors or micropapillary tumors. We sought to investigate the role of and associations between BRAF mutational status, extracellular signal regulated kinase activation, and p16(INK4A) expression in various types of ovarian serous tumors. We analyzed 29 typical ovarian serous borderline tumors, 8 micropapillary tumors, 4 low-grade invasive ovarian serous carcinomas, and 24 high-grade invasive ovarian serous carcinomas for the BRAF mutational status at codon 600; in addition, expression levels of the downstream signaling protein extracellular signal regulated kinase and the p16(INK4A) tumor suppressor protein were assessed by immunohistochemistry. There was a decline in p16(INK4A) expression from serous borderline tumors to micropapillary tumors with almost complete loss in low-grade invasive carcinomas. High-grade carcinomas had a variable p16(INK4A) expression pattern. We found a T1799A BRAF mutation in 12 typical serous borderline tumors (41%) and 1 micropapillary tumor (12.5%). No mutations were found in the low-grade and high-grade invasive carcinomas (0%). Among the typical borderline tumors, cases with BRAF mutations tended to have stronger p16(INK4A) expression compared with cases with wild-type BRAF. No other correlations were identified between the BRAF mutational status and expression levels of the analyzed proteins. Loss of p16(INK4A) expression may be a pathogenetic factor in the progression from serous borderline tumors to low-grade invasive carcinomas. The divergent molecular profiles support the theory that high-grade carcinomas are unrelated to serous borderline tumors or low-grade carcinomas.

The infrequent association of serous borderline tumors (SBTs) with invasive serous carcinoma has led to the view that SBTs are unrelated to invasive serous carcinoma. Nonetheless, mortality associated with SBTs is generally attributed to malignant transformation, and traditionally these tumors have been designated as "carcinomas of low malignant potential." Previous immunohistochemical studies evaluating p53 expression and molecular genetic studies evaluating mutational status have reported that p53 overexpression and mutations are infrequent in SBTs and occur in as many as 50% to 80% of invasive serous carcinomas. The different methodologies for determining p53 status and the failure to correlate the findings with tumor grade make these studies difficult to interpret. The current study was undertaken to overcome these deficiencies and to reconcile the relationship of SBTs to invasive serous carcinoma by performing a morphologic, immunohistochemical, and molecular genetic analysis comparing SBTs with low- and high-grade serous carcinoma. The molecular genetic analysis used a highly stringent, carefully designed nucleotide-sequencing method. A total of 96 sporadic serous tumors including 25 SBTs (11 atypical proliferative serous tumors and 14 intraepithelial low-grade serous carcinomas [noninvasive micropapillary serous carcinomas, MPSCs]), 12 low-grade serous carcinomas (invasive MPSCs), and 59 high-grade serous carcinomas were analyzed for their p53 mutational status of exons 5 to 9. Functional mutations, defined as mutations resulting in the alteration of the structure of the encoded protein, were detected in 30 of 59 (50.8%) high-grade serous carcinomas and 1 (8.3%) of 12 low-grade invasive serous carcinomas compared with 2 (8%) of 25 SBTs, both of these in intraepithelial low-grade serous carcinomas (noninvasive MPSCs). The similar frequency of p53 mutations in SBTs and low-grade invasive serous carcinomas in contrast to the significantly higher frequency of p53 mutations in high-grade serous carcinomas (P < 0.0005) suggests a common lineage for SBTs and low-grade invasive serous carcinomas and supports the view that SBTs are unrelated to the usual type of invasive serous carcinoma, which is a high-grade neoplasm. Mutational status was also correlated with p53 immunoreactivity. Although p53 immunoreactivity is generally higher in those specimens containing mutant p53, immunostaining is neither sufficiently specific nor sensitive enough to predict p53 mutations. The molecular genetic findings confirm our hypothesis of dual pathways of serous carcinogenesis based on previous analyses of KRAS and BRAF mutations on the same set of cases in which KRAS and BRAF mutations were found in 60% of SBTs and low-grade serous carcinoma but not in high-grade serous carcinomas. Based on these studies, we have proposed a model of serous carcinogenesis in which SBTs are the precursors of low-grade serous carcinomas whereas the usual type of invasive serous carcinoma is a high-grade neoplasm that develops "de novo" from in situ alterations in epithelial inclusion cysts.

Ovarian serous carcinoma (OSC) is the most common ovarian epithelial malignancy. Recently, a dualistic pathway of ovarian serous carcinogenesis has been proposed based on morphologic observations and molecular genetic analysis. In this scheme, low-grade OSC arises in a stepwise fashion from a benign serous cystadenoma through a usual serous borderline tumor through a micropapillary variant of serous borderline tumor. In contrast, the more common high-grade OSC arises de novo from the ovarian surface epithelium or the epithelium of cortical inclusion cysts with an as yet unrecognized precursor lesion. Although the division of OSC into low- and high-grade variants is gaining greater acceptance, and although there is accumulating molecular genetic evidence for this, there is little published information regarding a comparison of protein expression between these two types of OSC. In this study, we have investigated the immunohistochemical expression of a wide range of proteins in cases of low-grade (n = 22) and high-grade (n = 47) OSC. Antibodies used were p53, MIB1, BCL2, WT1, HER-2/neu, C-KIT, osteopontin, and survivin. For all antibodies, except MIB1, cases were scored as 0 (negative or occasional positive cells), 1+ (<10% cells positive), 2+ (10%-25% cells positive), 3+ (26%-50% cells positive), 4+ (51%-75% cells positive) or 5+ (>75% cells positive). For MIB1, the percentage of positive nuclei was calculated. There was a statistically significant higher expression of p53, MIB1, BCL2, HER-2/neu, and C-KIT in high-grade compared with low-grade OSC (P < 0.05). Thirty of 47 (64%) cases of high-grade OSC exhibited 5+ staining with p53 compared with 4 of 22 (18%) low-grade neoplasms. Twelve of 47 (26%) high-grade OSCs exhibited 5+ staining with BCL2 compared with 1 of 22 (5%) low-grade OSCs. The mean MIB1 proliferative index in high-grade OSCs was 55.4% compared with 23.0% in low-grade OSCs. Virtually all cases of both low-grade and high-grade OSCs exhibited diffuse nuclear positivity with WT1 and diffuse cytoplasmic positivity with survivin. Osteopontin expression was variable with no significant difference in expression between low-grade and high-grade OSC. Although expression of both HER-2/neu and C-KIT was significantly higher in high-grade compared with low-grade OSC, only rare cases exhibited strong positivity with these antibodies, which could be of therapeutic value in individual cases, although this would require additional molecular investigations. The significant differences in protein expression between low-grade and high-grade OSC provides further support for a different underlying pathogenesis. In particular, the differences in p53 immunoreactivity are in keeping with the observation that p53 gene mutation is more common in high-grade than low-grade OSC.

Low-grade (LG) serous ovarian carcinoma is believed to arise from serous borderline ovarian tumors; yet the progression from serous borderline tumors to LG serous ovarian carcinoma remains poorly understood. The purpose of this study was to identify differentially expressed genes between the 2 groups. Expression profiles were generated from 6 human ovarian surface epithelia, 8 serous borderline ovarian tumors (SBOTs), 13 LG serous ovarian carcinomas, and 24 high-grade (HG) serous ovarian carcinomas. The anterior gradient homolog 3 (AGR3) gene was found to be highly upregulated in serous borderline ovarian tumors. This finding was validated by real-time quantitative reverse-transcription polymerase chain reaction, Western blotting, and immunohistochemistry. Anti-AGR3 immunohistochemistry was performed on an additional 56 LG and 103 HG tissues, and the results were correlated with clinical data. Expression profiling determined that 1254 genes were differentially expressed (P<0.005) among SBOT, LG, and HG tumors. SBOTs exhibited robust positive staining for AGR3, with a lower percentage of tumor cells stained in LG and HG. Immunofluorescence staining indicated that AGR3 expression was limited to ciliated cells. Tumor samples with a high percentage (>10%) of AGR3 positively stained tumor cells were associated with improved longer median survival in both the LG (P=0.013) and HG (P=0.008) serous ovarian carcinoma groups. The progression of SBOT to LG serous ovarian carcinoma may involve the dedifferentiation of ciliated cells. AGR3 could serve as a prognostic marker for survival in patients with LG and HG serous ovarian carcinomas.

Ovarian low grade serous carcinoma: A case report

Mitogen-activated protein kinase (MAPK) plays a pivotal role in signal transduction. Activation of MAPK is regulated by upstream kinases including KRAS and BRAF, which are frequently mutated in low-grade ovarian serous carcinoma. This study evaluates the expression of active MAPK in ovarian serous carcinomas, with response to treatment and survival. Expression of active MAPK was assessed by immunohistochemistry in 207 cases of ovarian serous tumors. Immunoreactivity was correlated with tumor grade, mutational status of KRAS and BRAF, in vitro drug resistance, and clinical outcome. There was a lower frequency of expression of active MAPK in high-grade ovarian serous carcinomas as compared with low-grade serous tumors, including borderline tumors and low-grade serous carcinoma (P < 0.001). Active MAPK was present in all of the 19 low-grade tumors with either KRAS or BRAF mutations as well as in 14 (41%) of 34 tumors with wild-type KRAS and BRAF in both low- and high-grade carcinomas. Expression of active MAPK alone served as a good survival indicator in the 2-year follow-up (P = 0.037) but not in the 5-year follow-up (P = 0.145). However, a combination of expression of active MAPK and in vitro sensitivity of paclitaxel significantly correlated with a better prognosis in 5-year survival rate (P = 0.048) in patients with advanced-stage high-grade serous carcinoma. Active MAPK is more frequently expressed in low-grade than in high-grade ovarian serous carcinoma. Active MAPK serves as a good prognostic marker in patients with high-grade serous carcinomas.

DNA damage commonly occurs in cancer cells as a result of endogenous and tumor microenvironmental stress. In this study, we applied immunohistochemistry to study the expression of phosphorylated Chk2 (pChk2), a surrogate marker of the DNA damage response, in high grade and low grade of ovarian serous carcinoma. A phospho-specific antibody specific for threonine 68 of Chk2 was used for immunohistochemistry on a total of 292 ovarian carcinoma tissues including 250 high-grade and 42 low-grade serous carcinomas. Immunostaining intensity was correlated with clinicopathological features. We found that there was a significant correlation between pChk2 immunostaining intensity and percentage of pChk2 positive cells in tumors and demonstrated that high-grade serous carcinomas expressed an elevated level of pChk2 as compared to low-grade serous carcinomas. Normal ovarian, fallopian tube, ovarian cyst, and serous borderline tumors did not show detectable pChk2 immunoreactivity. There was no significant difference in pChk2 immunoreactivity between primary and recurrent high-grade serous carcinomas. In high-grade serous carcinomas, a significant correlation (P < 0.0001) in expression level (both in intensity and percentage) was found between pChk2 and Rsf-1 (HBXAP), a gene involved in chromatin remodeling that is amplified in high-grade serous carcinoma. Our results suggest that the DNA damage response is common in high-grade ovarian serous carcinomas, especially those with Rsf-1 overexpression, suggesting that Rsf-1 may be associated with DNA damage response in high-grade serous carcinomas.

Patients with ovarian serous cancer are usually younger and survive longer than patients with high-grade serous cancer. Unfortunately, most low-grade serous cancer patients eventually die of the disease because recurrent low-grade serous carcinoma is relative chemoresistant. So far, the known mutations identified in low-grade ovarian serous carcinomas and their putative precursor ovarian serous borderline tumors are BRAF and KRAS mutations. BRAF and KRAS mutations together have been identified in approximately 60% of serous borderline tumors and early stage low-grade serous carcinomas. However, BRAF mutation is rare in advanced-stage low-grade serous carcinomas. To further investigate the molecular pathogenesis of low-grade serous carcinoma, mutation analyses of 409 cancer related genes were performed in 21 low-grade ovarian serous carcinoma, 8 ovarian serous borderline tumors and one ovarian cystadenoma using next generation sequencer. A total of nineteen missense mutations were identified in 20 samples but ten samples had no detectable mutations. BRAF mutation was detected in 3 serous borderline tumors and one low-grade serous carcinoma. KRAS mutations were detected in three low-grade serous carcinomas. Other than BRAF and KRAS mutations, we also detected other prevalent mutations: ATRX mutations were detected in 3 low-grade ovarian serous carcinomas and a cystadenoma; KMT2C mutations were detected in 3 low-grade ovarian serous carcinomas; ATM mutations were detected in 2 low-grade ovarian serous carcinomas. Interestingly, both ATRX and MLL3 genes are involved in the chromatin remodeling. Moreover, both ATRX and ATM are involved in DNA damaging response. Thus, the pathogenesis of low-grade serous carcinoma may involve de-regulation of chromatin remodeling pathway and DNA damaging response. Further analysis of a large cohort of low-grade serous carcinomas for these prevalent mutations is ongoing. Citation Format: Yvonne TM Tsang, Daisy Izaguirre, Suet-Yan Kwan, Samuel C. Mok, David Gershenson, Kwong-Kwok Wong. Ovarian low grade serous cancer: Mutation analysis with a comprehensive 409 cancer gene panel. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1529. doi:10.1158/1538-7445.AM2014-1529

Low-grade serous ovarian carcinoma and its high-grade serous ovarian carcinoma counterpart differ in their precursor lesions, molecular profile, natural history, and response to therapies. As such, low-grade serous ovarian carcinoma...

Ovarian low-grade serous carcinoma (LGSC) is an entity with distinct pathologic and clinical features. The number of studies on this type of tumor is limited. In this article, we present our experience with 33 cases of ovarian LGSC with primary surgical treatment at our institution. For comparison, a cohort of ovarian high-grade serous carcinoma (HGSC) was also studied. Clinical information was obtained from the patients' charts or from the treating physicians. Hematoxylin and eosin slides were reviewed of 28 available LGSCs, and the following parameters were recorded: presence/absence of a serous borderline tumor (SBT), presence/absence of micropapillary/cribriform pattern (MP/CP), architectural pattern in the invasive component, and presence/absence of desmoplasia or fibrosis. The incidence of ovarian LGSC was 4.7%. LGSC patients ranged in age from 19 to 79 years (mean, 52 y), with 21.2% younger than 40 years. HGSC patients ranged in age from 38 to 90 years (mean, 62 y), with 1.6% younger than 40 years. LGSCs were staged as follows: stage I (2), stage III (23), and stage IV (8). Twenty-eight of 33 LGSC cases had concurrent SBT, with this component accounting for >50% of the neoplasm in 15 cases. In addition, MP/CP was noted in 19 cases. Invasion patterns included micropapillae (93%), cribriform nests (74%), elongated papillae (26%), glandular (44.4%), medium-sized papillae (33.3%), solid nests (22.2%), macropapillae (19%), and single cells (19%). In addition, desmoplasia (44.4%) and fibrosis (37%) were noted. Follow-up data ranging from 13 to 195 months (median 61.2 mo) were available on 30/33 LGSC patients: 18 (60%) were dead of disease; 1 (3.3%) was dead of other cause; 5 (16.7%) were alive with disease; and 6 (20%) had no evidence of disease. Follow-up data from 1 to 169 months (median 48 mo) were available on 185 HGSC patients: 132 (71.4%) were dead of disease; 3 (1.6%) were dead of other cause; 21 (11.4%) were alive with disease; and 29 (15.7%) had no evidence of disease. Ovarian LGSC is rare with a predilection for younger patients relative to HGSC. Most LGSC cases are associated with SBT with an MP/CP, and their invasive component usually contains a micropapillary pattern. Most patients with ovarian LGSC present with advanced-stage disease and have a short-term survival advantage over patients with HGSC (estimated 5 y survival: 62.3% vs. 43.9%). However, over a prolonged period of time, this survival advantage decreases (estimated 10 y survival: 21.2% vs. 22.7%).

Morphological subtypes of ovarian carcinoma: a review with emphasis on new developments and pathogenesis