Trefoil Factor 2 (TFF2) as a Surrogate Marker for Endocervical Gastric-type Carcinoma

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.

Gastric-type adenocarcinoma of the uterine cervix: clinical features and future directions

The concept of gastric-type mucinous carcinoma of the uterine cervix (GAS) has been accepted worldwide because of its aggressive clinical behaviour and the absence of high-risk human papilloma virus infection. The World Health Organization (WHO) 2020 classification divides cervical tumours into two categories: human papilloma virus-associated and human papilloma virus-independent. Hence, GAS is now classified as an human papilloma virus-independent gastric type. Because clinical studies have reported that GAS is refractory to conventional treatments such as chemotherapy and radiotherapy, especially at an advanced stage, and has aggressive features with widespread dissemination to unusual sites, such as the omentum, peritoneum and distant organs, it is urgent to establish new treatment strategies by comparing the molecular profiles of human papilloma virus-associated adenocarcinomas. A series of genetic mutations characteristic to GAS encourage the development of future treatment strategies such as targeted therapy and immunotherapy.

Current status and molecular biology of human papillomavirus-independent gastric-type adenocarcinoma of the cervix

This article reviews the findings of clinical studies on gastric-type adenocarcinoma of the cervix to date, outline the molecular biological features identified in recent studies, and discusses the future therapeutic strategies. Gastric-type adenocarcinoma of the cervix is a new classification in the World Health Organization 2014 classification. The World Health Organization 2020 classification further divides cervical tumors into two categories: human papillomavirus-associated and human papillomavirus-independent. Thus, gastric-type adenocarcinoma of the cervix is now classified as a human papillomavirus-independent gastric type. Clinical studies have reported that gastric adenocarcinoma of the cervix is refractory to conventional chemotherapy and radiotherapy, and it is desirable to elucidate its molecular biological mechanism. A series of gene mutations characteristic to the gastric-type adenocarcinoma of the cervix encourage the development of future treatment strategies.

Diagnostic accuracy of HIK1083 and MUC6 as immunohistochemical markers of endocervical gastric-type adenocarcinoma: A systematic review and meta-analysis

INTRODUCTION

HIK1083 and MUC6 have been used as immunohistochemical markers to differentiate gastric-type adenocarcinoma (GTAC) from other endocervical adenocarcinomas. We aimed to assess their diagnostic accuracy through a systematic review and meta-analysis.

METHODS

Three electronic databases were searched from their inception to July 2022 for all studies assessing the expression in endocervical GTAC vs other endocervical adenocarcinomas. Diagnostic accuracy was assessed as sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), diagnostic odds ratio (DOR), and area under the curve (AUC) on SROC curves.

RESULTS

Four studies with 343 patients were included. HIK1083 showed sensitivity= 0.64, specificity= 0.94, LR+ =8.30, LR-= 0.38, DOR= 33.36, AUC= 89.9%. MUC6 showed sensitivity= 0.51, specificity= 0.74, LR+ =1.96, LR-= 0.71, DOR= 3.48, AUC= 72.8%.

CONCLUSION

HIK1083 showed high specificity and low sensitivity as a marker of GTAC, with moderate overall accuracy; MUC6 showed moderate specificity and low sensitivity, with low overall accuracy.

Mucinous Proliferations of the Uterine Corpus: Comprehensive Appraisal of an Evolving Spectrum of Neoplasms

A variety of endometrial lesions may contain mucinous cells. Herein, the author reviews the literature on the classification and clinicopathologic significance of uterine corpus proliferations with a significant mucinous component, assesses the 2020 World Health Organization classification of such lesions, and presents a diagnostic framework. The key epithelial mucinous lesions include mucinous metaplasia, atypical mucinous glandular proliferation and mucinous carcinoma. Each of these categories are classifiable into "usual" and gastrointestinal subtypes, the latter being indicative of intestinal (presence of goblet cells) and/or gastric-type (abundant, pale eosinophilic or clear cytoplasm and well-defined cell borders) morphology. It has been proposed that at least focal expression of gastrointestinal immunohistochemical markers be required for all gastrointestinal type lesions, and for gastrointestinal type atypical mucinous glandular proliferation and carcinoma, minimality or absence of estrogen receptor expression, and the absence of an endometrioid component. Mucinous carcinomas of the usual type, in which >50% of the tumor is comprised of a mucinous component, are the most common. Morphologic subtypes include mucinous carcinoma with microglandular features and mucinous carcinoma with signet rings (signet ring carcinoma). Endometrioid carcinomas with a less than a 50% mucinous component are classified as endometrioid carcinoma with mucinous differentiation. Several studies have directly compared endometrioid and mucinous carcinomas, the latter presumably of the usual type, with respect to patient outcomes after treatment. All have found no difference in overall and disease free survival between these groups. However, three major studies have found mucinous carcinomas to be associated with a higher risk of lymph node metastases. Nineteen cases of mucinous carcinoma of the gastrointestinal type have been reported, and the limited data on their follow-up after primary treatment suggests that this subtype is more clinically aggressive and should accordingly be classified separately from mucinous carcinomas of the usual type. The morphologic spectrum of mucinous carcinoma of the gastrointestinal type is unclear and continues to evolve. Mucinous change, which may sometimes be extensive, may also be associated with papillary proliferation of the endometrium, adenomyoma of the endocervical type, atypical, and typical adenomyomas. In a curettage or biopsy, intestinal type mucinous epithelium may be indicative of any of the gastrointestinal lesions mentioned above, but may also represent samplings of uterine teratomas, yolk sac tumors, genital and extragenital adenocarcinomas with intestinal differentiation, or low-grade appendiceal mucinous neoplasms that secondarily involve the endometrium.

Squamous and Glandular Epithelial Tumors of the Cervix: A Pragmatical Review Emphasizing Emerging Issues in Classification, Diagnosis, and Staging

Squamous cell carcinoma is the most frequent epithelial malignant tumor of the cervix and among the most frequent neoplasm in women worldwide. Endocervical adenocarcinoma is the second most common malignancy. Both tumors and their precursors are currently classified based on human papillomavirus status, with prognostic and predictive value. Various prognostic biomarkers and alternative morphologic parameters have been recently described and could be used in the management of these patients. This pragmatical review highlights recent developments, emerging issues as well as controversial areas regarding the cause-based classification, diagnosis, staging, and prognostic parameters of epithelial malignant tumors of the cervix.

Claudin-18 as a Promising Surrogate Marker for Endocervical Gastric-type Carcinoma

HIK1083 and trefoil factor 2 (TFF2) are known to be expressed in gastric-type carcinoma (GAS), but they do not reliably mark all GASs, and focal expression can be missed in biopsy specimens. We aimed to investigate whether claudin-18 and alpha-methylacyl-CoA racemase (AMACR) could be surrogate markers to separate GAS from other types of endocervical adenocarcinoma (ECA) and to compare their usefulness with that of HIK1083 and TFF2. Claudin-18 and AMACR immunohistochemistry was performed, and the results were compared with that of TFF2 and HIK1083, using whole sections of 75 ECAs (22 GASs and 53 non-GASs) and 179 ECAs with tissue microarrays (TMAs). TMAs were built to simulate the assessment of immunohistochemical stains in small biopsies. Any membranous (claudin-18) or cytoplasmic/membranous (AMACR, TFF2, HIK1083) staining of >5% of tumor cells was considered positive. Of 75 ECAs with whole sections, claudin-18 was significantly more frequently expressed in GASs (21/22) compared with non-GASs (8/53) (P<0.01). In ECAs with TMAs, claudin-18 expression was significantly frequent in GASs (15/23, 65.2%) than in non-GASs (3/152, 2.0%; all usual-type) (P<0.01). All claudin-18-positive GASs showed intense staining except 1 case. Claudin-18 shared the same degree of sensitivity and specificity with HIK1083 and TFF2. Three clear cell carcinomas were positive for claudin-18, but none showed intense staining. AMACR was expressed in a subset of ECAs and showed no impact in distinguishing between GAS and other ECAs. Our results suggest that claudin-18 is a promising surrogate marker to separate GAS from other types of ECA, including clear cell carcinoma.

Immunohistochemistry in gynecologic carcinomas: Practical update with diagnostic and clinical considerations based on the 2020 WHO classification of tumors

This review provides an update on immunohistochemistry applications-diagnostic, prognostic, and predictive-in the pathology evaluation of gynecologic carcinomas. The 5th edition of the WHO Classification of Female Genital Tumors introduced important changes in the diagnostic classification of lower genital tract, endometrial, and ovarian carcinomas, with major influence on the routine pathology practice. Lower genital tract carcinomas and their precursor lesions are now classified based on their human papillomavirus (HPV)-associated and HPV-independent pathogenesis, reflecting the clinically significant prognostic differences and impacting the therapeutic decision-making. Immunohistochemical markers have an increasing role in the pathology evaluation of endometrial carcinomas: in addition to their traditional use in the differential diagnosis and histologic subtyping, they have also been recently advocated for prognostic classification as surrogates for the TCGA (The Cancer Genome Atlas) molecular groups. New entities - mesonephric-like adenocarcinoma and gastric (gastrointestinal)-type mucinous adenocarcinoma of the endometrium - have also been added and often require immunostains for diagnostic confirmation. Ovarian carcinomas frequently show overlapping morphologic patterns and heterogeneous appearance within the same tumor, necessitating immunohistochemical work-up. Beyond diagnostic applications, there is increasing clinical demand for screening of inherited cancer syndromes, prediction of prognosis and guiding targeted therapy. Practical issues and pitfalls related to mismatch repair protein immunohistochemistry, HER2, and PD-L1 testing are also discussed.

Massively parallel sequencing analysis of 68 gastric-type cervical adenocarcinomas reveals mutations in cell cycle-related genes and potentially targetable mutations

Gastric-type cervical adenocarcinoma (GCA) is an aggressive type of endocervical adenocarcinoma characterized by mucinous morphology, gastric-type mucin, lack of association with human papillomavirus (HPV) and resistance to chemo/radiotherapy. We characterized the landscape of genetic alterations in a large cohort of GCAs, and compared it with that of usual-type HPV-associated endocervical adenocarcinomas (UEAs), pancreatic adenocarcinomas (PAs) and intestinal-type gastric adenocarcinomas (IGAs). GCAs (n = 68) were subjected to massively parallel sequencing targeting 410-468 cancer-related genes. Somatic mutations and copy number alterations (CNAs) were determined using validated bioinformatics methods. Mutational data for UEAs (n = 21), PAs (n = 178), and IGAs (n = 148) from The Cancer Genome Atlas (TCGA) were obtained from cBioPortal. GCAs most frequently harbored somatic mutations in TP53 (41%), CDKN2A (18%), KRAS (18%), and STK11 (10%). Potentially targetable mutations were identified in ERBB3 (10%), ERBB2 (8%), and BRAF (4%). GCAs displayed low levels of CNAs with no recurrent amplifications or homozygous deletions. In contrast to UEAs, GCAs harbored more frequent mutations affecting cell cycle-related genes including TP53 (41% vs 5%, p < 0.01) and CDKN2A (18% vs 0%, p = 0.01), and fewer PIK3CA mutations (7% vs 33%, p = 0.01). TP53 mutations were less prevalent in GCAs compared to PAs (41% vs 56%, p < 0.05) and IGAs (41% vs 57%, p < 0.05). GCAs showed a higher frequency of STK11 mutations than PAs (10% vs 2%, p < 0.05) and IGAs (10% vs 1%, p < 0.05). GCAs harbored more frequent mutations in ERBB2 and ERBB3 (9% vs 1%, and 10% vs 0.5%, both p < 0.01) compared to PAs, and in CDKN2A (18% vs 1%, p < 0.05) and KRAS (18% vs 6%, p < 0.05) compared to IGAs. GCAs harbor recurrent somatic mutations in cell cycle-related genes and in potentially targetable genes, including ERBB2/3. Mutations in genes such as STK11 may be used as supportive evidence to help distinguish GCAs from other adenocarcinomas with similar morphology in metastatic sites.