PAX8 and PAX2 Expression in Endocervical Adenocarcinoma In Situ and High-Grade Squamous Dysplasia

Hepatocyte nuclear factor 4α as a sensitive marker for uterine endocervical adenocarcinomas and their precursors

CONTEXT

Hepatocyte nuclear factor (HNF)-4α is a marker of gastrointestinal tumor differentiation; however, its expression in endocervical tumors remains unclear.

OBJECTIVE

We aimed to assess the utility of HNF4α expression as a marker for endocervical adenocarcinomas (ECAs) and adenocarcinoma in situs (AISs), and to establish a minimal panel for distinguishing them from nonneoplastic endocervical glandular lesions and metastases.

DESIGN

HNF4α expression was analyzed immunohistochemically (positive, H-score ≥10) in 323 tissue samples: 57 endocervical neoplasms including 35 glandular neoplasms and 22 squamous neoplasms, 144 nonneoplastic endocervical lesions, and 122 tumors from other organs. The panel for distinguishing endocervical glandular neoplasms from nonneoplastic glands and from metastases comprised HNF4α, p16, CDX2, and SATB2; staining was assessed.

RESULTS

HNF4α was expressed significantly in ECAs and AISs, both HPV-independent and -associated types, but not in nonneoplastic glandular and squamous lesions (p < 0.05). The immunohistochemical detection sensitivity and specificity for endocervical ECA and AIS were 77% and 95%, respectively. For AIS alone, these were 79% and 94%, and for ECA alone, 75% and 94%, respectively. Either HNF4α(+) or p16(+) or double positive identified endocervical gland and squamous neoplasms (sensitivity, 96%; specificity, 76%). HNF4α(+) and SATB2(-) and CDX2(-) profiles suggested ECAs (sensitivity, 69%; specificity, 88%). HNF4α(+) and SATB2(+) or CDX2(+) profiles suggested adenocarcinomas of the gastrointestinal or genital tract (sensitivity, 81%; specificity, 88%).

CONCLUSIONS

HNF4α is a promising marker for detecting both HPV-independent and -associated ECAs and AIS with high accuracy. Its combination with p16, CDX2, and SATB2 has potential use in diagnostic panels.

Paired box proteins as diagnostic biomarkers for endocervical adenocarcinoma

In this editorial, we commented on the article by Akers et al published in the recent issue of the World Journal of Clinical Cases. We focused specifically on the role of the transcription factor paired box protein 8 (PAX8) belonging to the family PAX in the carcinogenesis of a gynecologic tumor, endocervical adenocarcinoma, arising from the tissue of mesonephric origin, and the potential diagnostic value for the same type of neoplasms. The global vaccination program of human papillomavirus (HPV) has dramatically reduced the incidence of cervical cancer, including cases of adenocarcinoma. The type of adenoid epithelial origin has a lower frequency of HPV detection but tends to be more aggressive and fatal. Cases of endocervical adenocarcinoma occurring in females of menopause age have been described in the 2023 volume of the World Journal of Clinical Cases and in our study recently published in Oncol Lett. The histopathological findings and immunohistochemical assays showed that the lesions had glandular morphology, and the specimens in these two reports were immunohistochemically positive for the transcription factor PAX8, albeit that they had opposing expression profiles of tumor suppressor p16 and estrogen receptor and the presence of the HPV genome. The presence of a mucin protein, MUC 5AC, as revealed in both studies suggested target molecules for the diagnosis of mucinous adenoid type of uterine tumor and other histological origins. The clinical outcome was unfavorable due to metastasis and recurrence. This prompted the improvement of the antitumor modality, with the introduction of precise targeting therapy. Mucin has now been reported to be the therapeutic target for adenocarcinomas.

The evolving landscape of immunohistochemistry in cervical and uterine carcinoma in gynecologic oncology: current status and future directions

Immunohistochemistry (IHC) has become an indispensable tool in routine gynecological pathology, particularly with the advancements in molecular understanding and histological classification of gynecological cancers. This evolution has led to new immunostainings for diagnostic and classification purposes. This review describes the diagnostic utility of IHC in gynecological neoplasms, drawing insights from literature reviews, personal experiences, and research findings. It delves into the application of IHC in resolving morphologically equivocal cases, emphasizing its role in achieving an accurate diagnosis. The selection of appropriate immunomarkers for common scenarios encountered in gynecological pathology aids pathologists in navigating complex cases. Specifically, we focus on cervical and endometrial malignancies, elucidating the molecular rationale behind the use of specific immunohistochemical markers. An updated overview of essential immunohistochemical markers provides knowledge for precise diagnosis and classification of gynecological cancers. This review serves as a valuable resource for clinicians and researchers involved in the management and study of gynecological malignancies, facilitating improved patient care and outcomes.

Gastric-type glandular lesions of the female genital tract excluding the cervix: emerging pathological entities

In the last two decades or so, a spectrum of benign, premalignant and malignant cervical glandular lesions exhibiting gastric differentiation has been described, with gastric-type adenocarcinoma representing the most common human papillomavirus (HPV)-independent cervical adenocarcinoma. More recently, limited literature has reported a variety of gastric-type glandular lesions at other sites within the female genital tract and, as in the cervix (the most common site for these lesions), a spectrum of benign, premalignant and malignant lesions has been proposed. We provide an update and review of the emerging spectrum of gastric-type glandular lesions at female genital tract sites other than the cervix. In the endometrium, putative gastric-type glandular lesions include mucinous metaplasia of gastric-type, atypical mucinous proliferation of gastric-type and gastric-type adenocarcinoma. Similarly in the vagina, gastric-type adenosis, atypical adenosis and adenocarcinoma have been described. There have also been occasional reports of gastric-type lesions involving the ovary and fallopian tube. We provide guidance on how to recognise gastric-type lesions morphologically and immunophenotypically and stress that sometimes these lesions occur at more than one site within the female genital tract (synchronous/multifocal gastric-type lesions of the female genital tract), sometimes in association with Peutz-Jeghers syndrome.

Paired-Box Gene 8 (PAX8) and Its Association With Epithelial Carcinomas

Cancer is the second most common culprit of mortality in the United States and epithelial carcinomas are considered as one of the most predominant types of cancer. The association between epithelial cancers and paired-box gene 8 (PAX8) has been studied significantly before. PAX8 belongs to the paired-box gene family, which plays an important role in the organogenesis of different body organ systems, especially the thyroid gland, the renal system, and the Müllerian system. Immunohistochemical staining is being used to detect PAX8 expression in different epithelial cancers and differentiate them from PAX8-negative tumors. In follicular, papillary, and anaplastic thyroid carcinomas, targeting the PAX8/peroxisome proliferator-activated receptors (PPARs) fusion protein is being considered as a potential mechanism for therapy. Moreover, because of its high expression in primary ovarian cancers, PAX8 is being considered as a target for ovarian cancer treatment as well. More studies are needed to test the possibility of using PAX8 as a possible target for managing endometrial carcinomas. In this article, we review the functions of the PAX8 gene, how its mutations lead to the development of certain epithelial carcinomas, how it can be used as a diagnostic or a prognostic marker, and its potential as a therapeutic target for these cancers.

Atypical Microglandular Hyperplasia of Endocervix as the Presenting Feature of Plasminogen Deficiency

A 30-yr-old patient with no significant past medical history presented with postcoital bleeding and was found to have fibrinous pseudomembranous lesions overlying and partly in continuity with the endocervical mucosa. Histologically, these were characterized by an atypical microglandular proliferation that was associated with extensive fibrinous exudate and a prominent neutrophil polymorph infiltrate. Ligneous stromal alteration was not identified but the changes prompted hematologic review which confirmed plasminogen deficiency. A subsequent endometrial biopsy also demonstrated degenerate glands within a fibrin-rich matrix. This is the third case demonstrating an association between atypical endocervical microglandular hyperplasia and plasminogen deficiency. The diagnosis should also be considered when biopsies demonstrate exuberant fibrin exudate even if ligneous disease is not present.

A Comprehensive Review of Biomarker Use in the Gynecologic Tract Including Differential Diagnoses and Diagnostic Pitfalls

Morphologic (ie, hematoxylin and eosin) evaluation of the Mullerian tract remains the gold standard for diagnostic evaluation; nevertheless, ancillary/biomarker studies are increasingly utilized in daily practice to assist in the subclassification of gynecologic lesions and tumors. The most frequently utilized "biomarker" technique is immunohistochemistry; however, in situ hybridization (chromogenic and fluorescence), chromosomal evaluation, and molecular analysis can also be utilized to aid in diagnosis. This review focuses on the use of immunohistochemistry in the Mullerian tract, and discusses common antibody panels, sensitivity and specificity of specific antibodies, and points out potential diagnostic pitfalls when using such antibodies.

Pseudolaric acid B inhibits PAX2 expression through Wnt signaling and induces BAX expression, therefore promoting apoptosis in HeLa cervical cancer cells

Objectives

Pseudolaric acid B (PAB) has been shown to inhibit the growth of various tumor cells, but the molecular details of its function are still unknown. This study investigated the molecular mechanisms by which PAB induces apoptosis in HeLa cells.

Methods

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were performed to investigate the effect of PAB treatment in various cervical cancer cell lines. Annexin V/propidium iodide staining combined with flow cytometry and Hoechst 33258 staining were used to assess PAB-induced apoptosis. Additionally, we performed bioinformatics analyses and identified a paired box 2 (PAX2) binding site on the BAX promoter. We then validated the binding using luciferase and chromatin immunoprecipitation assays. Finally, western blotting assays were used to investigate PAB effect on the Wnt signaling and the involved signaling molecules.

Results

PAB promotes apoptosis and downregulates PAX2 expression in HeLa cells in a time- and concentration-dependent manner. PAX2 binds to the promoter of BAX and inhibits its expression; therefore, PAX2 inhibition is associated with increased levels of BAX, which induces apoptosis of HeLa cells via the mitochondrial pathway. Additionally, PAB inhibits classical Wnt signaling.

Conclusion

PAB effectively inhibits Wnt signaling and PAX2 expression, and increases BAX levels, which induce apoptosis in HeLa cells. Therefore, PAB is a promising natural molecule for the treatment of cervical cancer.

Emerging relationships between papillary proliferation of the endometrium and endometrial carcinoma: evidence from an immunohistochemical and molecular analysis

Papillary proliferation of the endometrium (PPE) is an uncommon lesion that frequently shows mucinous metaplasia. PPE occasionally has concurrent or preceding endometrial hyperplasia and carcinomas, but there is little molecular evidence to support the relationships between PPEs and endometrial neoplasia. In this study, we analyzed the clinicopathological and immunohistochemical features in 30 PPEs (22 simple PPEs and 8 complex papillary hyperplasia (CPH)). Hotspot mutations of KRAS, PI3KCA, AKT1, PTEN (exons 3, 5, and 7), and ARID1A (exons 1 and 14) were detected by pyrosequencing or bidirectional Sanger sequencing. We found that endometrial hyperplasia and carcinoma were more common in CPHs (4/6, 66.7%) than in simple PPEs (4/21, 19.0%) (p < 0.05). Compared with the adjacent normal endometrium, PPEs frequently showed loss of PAX2 (56.7%) and PTEN (10%) expression, diffuse p16 expression (36.7%), decreased PR expression (84.3%), and lower Ki67 labeling index (median 1%, range 1-15%). Simple PPEs and CPHs had similar immunohistochemical features (p > 0.05). KRAS mutations were identified in 14 PPEs and 1 concurrent endometrial carcinoma. The prevalence of KRAS mutations was not statistically different between simple PPEs (10/21, 45.5%) and CPHs (4/8, 50%) (p > 0.05), but was higher in PPEs displaying mucinous metaplasia (12/24, 50%) than in those without (2/6, 33.3%) (p < 0.05). One simple PPE with a KRAS mutation had an AKT1 mutation. No PPEs demonstrated mutations in PI3KCA, PTEN, and ARID1A. In conclusion, both simple PPE and CPH share some common molecular alterations with endometrial neoplasia, in which, KRAS mutations might be a driver.

Does Strong and Diffuse PAX-8 Positivity Occur in Primary Lung Carcinoma? An Immunohistochemical Study of 418 Cases and Review of the Literature

Although rare cases of PAX-8-positive primary lung carcinoma have been reported, details of staining distribution and intensity in such cases are limited. The aim of this study was to determine whether strong and diffuse PAX-8 staining can occur in primary lung carcinoma. Immunohistochemical staining for PAX-8 (Rabbit polyclonal, 10336-1-AP; Proteintech) was performed on whole-tissue sections from 418 resected primary lung carcinomas. PAX-8 was positive in 5/418 (1.2%) cases, all of which were large cell neuroendocrine carcinomas. Staining was weak to moderate in all 5 cases, and was seen in 5% to 30% of tumor cells. All other primary lung carcinomas (413/418) were negative for PAX-8. This study-the largest series of PAX-8-stained whole-tissue sections of primary lung carcinoma to date-shows that strong and diffuse staining for PAX-8 does not occur in primary lung carcinoma of any type. This staining pattern in a carcinoma in a lung specimen provides strong evidence of nonpulmonary origin.

Cervical Adenocarcinoma: Diagnosis of Human Papillomavirus-Positive and Human Papillomavirus-Negative Tumors

CONTEXT

- Cervical adenocarcinomas span a diverse group of tumors with several distinct histologic tumor types, which include endocervical, endometrioid, intestinal, villoglandular, gastric, signet ring, serous, clear cell, and mesonephric. Diagnosis of cervical adenocarcinoma, especially early diagnosis, poses a significant challenge.

OBJECTIVE

- To review the pathogenesis, diagnostic criteria, immunohistochemical markers, and differential diagnosis of various subtypes of human papillomavirus (HPV)-positive and HPV-negative cervical adenocarcinomas. The paper presents a concise summary of the issues that may be particularly difficult in histopathologic diagnosis, such as differentiating neoplastic lesions from benign mimics, determining the tumor type, differentiating early invasive lesions from adenocarcinoma in situ, measuring the depth of invasion, and, finally, differentiating primary cervical adenocarcinoma from uterine endometrioid adenocarcinoma and tumors metastatic from other primary sites.

DATA SOURCES

- The study employed a PubMed search of recently published reports.

CONCLUSIONS

- Early detection of HPV-positive tumor types may be aided with the expansion of HPV testing; however, early diagnosis of HPV-negative cervical adenocarcinomas will continue to pose a challenge and may require the development of additional molecular testing techniques.

A Detailed Immunohistochemical Analysis of a Large Series of Cervical and Vaginal Gastric-type Adenocarcinomas

Adenocarcinomas exhibiting gastric differentiation represent a recently described and uncommon subtype of non-human papillomavirus (HPV)-related cervical adenocarcinoma. They comprise a spectrum from a well-differentiated variant (adenoma malignum/mucinous variant of minimal deviation adenocarcinoma) to a more poorly differentiated overtly malignant form, generally referred to as gastric-type adenocarcinoma. Rarely, such tumors have also been described as primary vaginal neoplasms. Gastric-type adenocarcinomas exhibit considerable morphologic overlap with adenocarcinomas originating outside the female genital tract, especially mucinous adenocarcinomas arising in the pancreas and biliary tract. Moreover, they often metastasize to unusual sites, such as the ovary and peritoneum/omentum, where they can be mistaken for metastatic adenocarcinomas from other, nongynecologic sites. There is little information regarding the immunophenotype of gastric-type adenocarcinomas, and knowledge of this is important to aid in the distinction from other adenocarcinomas. In this study, we undertook a detailed immunohistochemical analysis of a large series of cervical (n=45) and vaginal (n=2) gastric-type adenocarcinomas. Markers included were cytokeratin (CK)7, CK20, CDX2, carcinoembryonic antigen, CA125, CA19.9, p16, estrogen receptor, progesterone receptor, MUC6, PAX8, PAX2, p53, hepatocyte nuclear factor 1 beta, carbonic anhydrase IX, human epidermal receptor 2 (HER2), and mismatch repair (MMR) proteins. All markers were classified as negative, focal (<50% of tumor cells positive), or diffuse (≥50% tumor cells positive) except for p53 (classified as "wild-type" or "mutation-type"), HER2 (scored using the College of American Pathologists guidelines for gastric carcinomas), and MMR proteins (categorized as retained or lost). There was positive staining with CK7 (47/47-45 diffuse, 2 focal), MUC6 (17/21-6 diffuse, 11 focal), carcinoembryonic antigen (25/31-12 diffuse, 13 focal), carbonic anhydrase IX (20/24-8 diffuse, 12 focal), PAX8 (32/47-20 diffuse, 12 focal), CA125 (36/45-5 diffuse, 31 focal), CA19.9 (11/11-8 diffuse, 3 focal), hepatocyte nuclear factor 1 beta (13/14-12 diffuse, 1 focal), CDX2 (24/47-4 diffuse, 20 focal), CK20 (23/47-6 diffuse, 17 focal), and p16 (18/47-4 diffuse, 14 focal). Most cases were negative with estrogen receptor (29/31), progesterone receptor (10/11), PAX2 (18/19), and HER2 (25/26). p53 showed "wild-type" and "mutation-type" staining in 27 of 46 and 19 of 46 cases, respectively. MMR protein expression was retained in 19 of 20 cases with loss of MSH6 staining in 1 patient with Lynch syndrome. Molecular studies for HPV were undertaken in 2 tumors, which exhibited diffuse "block-type" immunoreactivity with p16, and both were negative. This is the first detailed immunohistochemical study of a large series of gastric-type adenocarcinomas of the lower female genital tract. Our results indicate immunophenotypic overlap with pancreaticobiliary adenocarcinomas but suggest that PAX8 immunoreactivity may be especially useful in distinguishing gastric-type adenocarcinomas from pancreaticobiliary and other nongynecologic adenocarcinomas, which are usually negative. Diffuse "block-type" p16 immunoreactivity in a cervical adenocarcinoma is not necessarily indicative of a high-risk HPV-associated tumor.

PAX8 is transcribed aberrantly in cervical tumors and derived cell lines due to complex gene rearrangements

The transcription factor PAX8, a member of the paired box-containing gene family with an important role in embryogenesis of the kidney, thyroid gland and nervous system, has been described as a biomarker in tumors of the thyroid, parathyroid, kidney and thymus. The PAX8 gene gives rise to four isoforms, through alternative mRNA splicing, but the splicing pattern in tumors is not yet established. Cervical cancer has a positive expression of PAX8; however, there is no available data determining which PAX8 isoform or isoforms are present in cervical cancer tissues as well as in cervical carcinoma-derived cell lines. Instead of a differential pattern of splicing isoforms, we found numerous previously unreported PAX8 aberrant transcripts ranging from 378 to 542 bases and present in both cervical carcinoma-derived cell lines and tumor samples. This is the first report of PAX8 aberrant transcript production in cervical cancer. Reported PAX8 isoforms possess differential transactivation properties; therefore, besides being a helpful marker for detection of cancer, PAX8 isoforms can plausibly exert differential regulation properties during carcinogenesis.

PAX8 expression in uterine adenocarcinomas and mesonephric proliferations

PAX8 is a useful immunohistochemical marker for the diagnosis of gynecologic tract malignancies. Several studies have described PAX8 expression in a wide variety of epithelial neoplasms, including ovarian and endometrial carcinomas. The goal of this study was to evaluate PAX8 expression in various types of uterine adenocarcinomas and mesonephric proliferations. Ninety-four cases of uterine adenocarcinomas (52 endometrial endometrioid carcinomas, 21 endometrial serous carcinomas, and 21 human papillomavirus-related endocervical carcinomas), 11 cases of benign mesonephric proliferations (remnants/hyperplasia), and normal endometrial and endocervical glandular epithelium in 58 cases were studied. Immunohistochemical staining was performed with the rabbit polyclonal anti-PAX8 antibody. All adenocarcinoma groups demonstrated a high frequency of PAX8 expression but with relatively high variability in the extent of staining among different subtypes. Both serous carcinomas and endometrioid carcinomas were positive in most cases (95% and 96%, respectively), but serous carcinomas displayed a significantly higher level of expression (immunohistochemical composite scores based on combined extent and intensity of expression) compared with endometrioid carcinomas (mean immunohistochemical composite scores: 8.3 vs. 5.3, respectively; P<0.006). Endocervical adenocarcinomas also had a high frequency of PAX8 expression (86% of cases), but the level of expression was significantly less than that of endometrial adenocarcinomas (mean immunohistochemical composite scores: 2.9 vs. 5.3-8.3, respectively; P<0.004). Among benign glandular epithelia, normal endocervical glands exhibited a significantly lower level of expression compared with either normal endometrial glands or benign mesonephric proliferations (mean immunohistochemical composite scores: 2.6 vs. 6.6-11.2, respectively; P<0.0006). We conclude that PAX8 is expressed in the vast majority of uterine adenocarcinomas, including those of both endometrial and endocervical origin, and that the level of expression based on combined extent and intensity is highest in endometrial serous carcinoma and lowest in endocervical adenocarcinoma. However, the high prevalence of PAX8 expression in the various types of uterine adenocarcinomas precludes use of this marker for distinguishing these tumors. In extrauterine sites, PAX8 can serve as a useful marker for adenocarcinomas of uterine origin (also positive in the majority of ovarian carcinomas), being most sensitive for identification of endometrial adenocarcinomas (both serous and endometrioid). The sensitivity for identifying metastatic endocervical adenocarcinomas is likely less and dependent on the degree to which the significantly lower extent of expression in these tumors is maintained in metastatic sites.