Gastric gland mucin-specific O-glycan expression decreases as tumor cells progress from lobular endocervical gland hyperplasia to cervical mucinous carcinoma, gastric type

Decreased expression of TFF2 and decreased αGlcNAc glycosylation are malignant biomarkers of pyloric gland adenoma of the duodenum

Pyloric gland adenoma (PGA) is a duodenal neoplasm expressing MUC6 and is often associated with high-grade dysplasia and adenocarcinoma. MUC6 secreted from the pyloric gland cells carries unique O-glycans exhibiting terminal α1,4-linked N-acetylglucosamine residues (αGlcNAc). The small peptide trefoil factor 2 (TFF2) is also secreted from pyloric gland cells and binds to αGlcNAc. We recently demonstrated that αGlcNAc serves as a tumor suppressor for gastric neoplasm including PGA, but the significance of TFF2 expression remains unknown. We examined 20 lesions representing low- and high-grade PGA in 22 cases by immunohistochemistry for αGlcNAc, TFF2, MUC6, MUC5AC, MUC2 and p53. αGlcNAc, TFF2 and MUC6 were co-expressed on the cell surface and a dot-like pattern in the cytosol in low-grade PGA lesions. High-grade PGA also expressed MUC6, but reduced αGlcNAc and TFF2 expression. The ratios of αGlcNAc or TFF2 to MUC6 score in high-grade PGA were significantly lower than low-grade PGA (P < 0.001). Co-expression of αGlcNAc-glycosylated MUC6 and TFF2 in PGA suggests the existence of αGlcNAc/TFF2 form complex in PGA cells, a finding consistent with our observations in non-neoplastic Brunner's gland cells. The decreased αGlcNAc and TFF2 expression are associated with high grade atypical cells, indicative of the malignant potential of PGA.

Stepwise progression of invasive mucinous adenocarcinoma based on radiological and biological characteristics

INTRODUCTION

Invasive mucinous lung adenocarcinoma (IMA) has unique radiological findings and pathological characteristics. IMA is classified into solitary and pneumonic types; however, it is unclear whether these are biologically identical.

METHODS

A single-center retrospective analysis was performed for 70 IMA patients (solitary type [n = 38] and pneumonic type [n = 32]) who underwent pulmonary resection between January 2010 and December 2018. We compared clinical and biological characteristics between the two types.

RESULTS

The frequencies of genetic alternations such as EGFR, KRAS, BRAF, GNAS, ERBB2, TP53, NRG1, and MET were not different. Immunohistochemically, expression of MUC1 was significantly more common in the pneumonic type (5.0% versus 20.0%, p = 0.01) and diffuse MUC6 positive in the solitary type (39.0% versus 13.0%, p = 0.02). We further classified solitary types into those with or without ground-glass opacity (GGO) and pneumonic types into those with or without crazy-paving appearance (CPA), and evaluated their surgical outcomes. Five-year overall survival and relapse free survival rates were 95.8%/86.6%, 64.3%/70.7%, 74.6%/68.9%, and 50.0%/28.6% in patients with solitary type with GGO, solitary type without GGO, pneumonic type without CPA, and pneumonic type with CPA, respectively.

CONCLUSIONS

There were no differences in genetic alternations; however, mucin expression pattern was different. Surgical outcomes were different according to the presence of GGO in the solitary type and the presence of CPA in the pneumonic type. These findings suggested a stepwise progression from solitary to pneumonic IMA.

Case Report: Pelvic mass and massive ascites as the first symptom in cervical adenocarcinoma: report of two cases and literature review

Cervical adenocarcinoma accounts for 10%-25% of total cases of cervical carcinoma. But in recent years, the incidence of adenocarcinoma has risen both proportionally and absolutely. Clinically, most cervical adenocarcinoma show no symptom or present with abnormal uterine bleeding or vaginal discharge, similar to squamous cell carcinoma. What different about it is that cervical cytological testing demonstrates a high false-negative rate of cervical adenocarcinoma, potentially leading to the failure in detecting in early stage. This report presents two cases both with pelvic masses, and massive ascites served as the initial symptom, which is similar to the clinical symptom of ovarian cancer, but ultimately diagnosed with cervical adenocarcinoma through surgical specimens. There are few literature reports on this situation. Hence, a literature review also has been performed to improve the recognition for cervical adenocarcinoma presenting with pelvic masses and massive ascites, and to avoid misdiagnosis.

Lobular Endocervical Glandular Hyperplasia, a mimicker and potential pitfall for HPV-independent well differentiated Gastric-type Endocervical Adenocarcinoma: Case report and literature review focusing on histology, immunophenotype, and molecular findings

Lobular glandular endocervical hyperplasia is an uncommon benign entity within the spectrum of gastric-type endocervical lesions. We report a case of a 48-year-old woman who presented with a palpable mass and watery vaginal discharge. Ultrasound revealed an 8 cm × 4 cm × 3 cm multicystic mass affecting the cervix, and hysterectomy was performed. The well-delimited multicystic, mucinous mass distorted the entire cervix. Microscopically, endocervical glandular proliferation with a lobular architecture was observed. The glands were lined with a single layer of tall, mucin-rich, columnar cells with basal and bland nuclei. The lesion was positive for MUC6 marker and hormonal receptors were negative, while P53 expression was normal. Three years later, the patient remained disease free. Here, we discuss the differential diagnosis between lobular glandular endocervical hyperplasia and similar conditions, particularly gastric-type endocervical adenocarcinoma, and review the literature focusing on the molecular pathways underlying gastric-type endocervical lesions. This case highlights the importance of accurate diagnosis to ensure favorable outcomes.

MUC13 promotes the development of esophageal cancer by upregulating the expression of O-glycan process-related molecules

BACKGROUND

Esophageal cancer is one of the most common malignant tumors in the world, which is characterized by poor prognosis, aggressiveness, and poor survival. Mucin 13 (MUC13) is a member of the membrane-bound mucin and located on chromosome 3q21.2 and consists of α and β subunits. It has been found that MUC13 is overexpressed in a variety of tumor cells and acts a vital role in the invasiveness and malignant progression of several types of tumors. However, the role and regulatory mechanism of MUC13 in the progression of esophageal cancer remain unclear.

METHODS

The expression level of MUC13 was detected in 15 esophageal cancer tissues and 15 pairs of adjacent nontumor tissues by immunohistochemistry (IHC). In addition, the expression of MUC13 mRNA level in human esophageal cancer cell lines (EC9706 and ECA109 and TE-1) was measured by qRT-PCR. In vitro, after silencing MUC13 with lentiviral interference technology, CCK8 assay, clone formation assay, and flow cytometry were applied to investigate the proliferation activity, clone formation ability and anti-apoptosis ability of EC9706 and ECA109 cells. The tumor xenograft growth assay was used to confirm the influence of MUC13 knockdown on the growth of esophageal tumors in vivo. The qRT-PCR assay and western blot experiments were taken to study the mechanism of MUC13 regulating the proproliferation and antiapoptotic of esophageal cancer.

RESULTS

The results showed that MUC13 was overexpressed in esophageal cancer tissues and cell lines (EC9706 and ECA109 and TE-1), especially in EC9706 and ECA109 cells, but low expressed in human esophageal epithelial cell line (HEEC). Next, silencing MUC13 inhibits proliferation, blocks cell cycle progression, and promotes cell apoptosis in vitro, and restrains the growth of esophageal cancer tissues in vivo. Finally, MUC13 affects the proproliferation and antiapoptotic by regulating the expression of GLANT14, MUC3A, MUC1, MUC12, and MUC4 that closely related to O-glycan process.

CONCLUSIONS

This study proved that MUC13 is an important molecule that regulates the O-glycan process and then affects the progress of esophageal cancer. MUC13 may be a novel therapeutic target for patients with esophageal cancer.

α1,4-linked N-acetylglucosamine suppresses gastric cancer development by inhibiting MUC1-mediated signaling

Gastric cancer is the second leading cause of cancer deaths worldwide, and more understanding of its molecular basis is urgently needed. Gastric gland mucin secreted from pyloric gland cells, mucous neck cells, and cardiac gland cells of the gastric mucosa harbors unique O‐glycans carrying terminal α1,4‐linked N‐acetylglucosamine (αGlcNAc) residues. We previously reported that αGlcNAc loss correlated positively with poor outcomes for patients with differentiated‐type gastric cancer. However, the molecular mechanisms underlying these outcomes remained poorly understood. Here, we examined the effects of upregulated αGlcNAc expression on malignant phenotypes of the differentiated‐type gastric cancer cell lines, AGS and MKN7. Upregulation of αGlcNAc following ectopic expression of its biosynthetic enzyme attenuated cell proliferation, motility, and invasiveness of AGS and MKN7 cells in vitro. Moreover, AGS cell tumorigenicity was significantly suppressed by αGlcNAc overexpression in a xenograft model. To define the molecular mechanisms underlying these phenotypes, we investigated αGlcNAc binding proteins in AGS cells and identified Mucin‐1 (MUC1) and podocalyxin. Both proteins were colocalized with αGlcNAc on human gastric cancer cells. We also found that αGlcNAc was bound to MUC1 in murine normal gastric mucosa. When we assessed the effects of αGlcNAc binding to MUC1, we found that αGlcNAc blocked galectin‐3 binding to MUC1, phosphorylation of the MUC1 C‐terminus, and recruitment of Src and β‐catenin to that C‐terminus. These results suggest that αGlcNAc regulates cancer cell phenotypes by dampening MUC1 signal transduction.

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.

MUC6 expression is a preferable prognostic marker for invasive mucinous adenocarcinoma of the lung

Gastric gland mucin consists of core protein MUC6 with residues heavily glycosylated by unique O-glycans carrying α1,4-linked N-acetylglucosamine (αGlcNAc). αGlcNAc-glycosylated MUC6 protein is seen in normal gastric and duodenal glands. Decreased αGlcNAc glycosylation on MUC6-positive tumor cells is often observed in premalignant lesions of the stomach, pancreas, and bile duct, and decreased MUC6 expression is seen in invasive cancer of these organs. Lung cancer (LC) is the most common cause of cancer death worldwide. Recently, the adenocarcinoma subtype has become the most common histological subtype of LC, and one of its invasive forms is invasive mucinous adenocarcinoma (IMA). Currently, prognostic markers of LC IMA are unknown. Here, we analyzed MUC5AC, MUC6, and αGlcNAc expression in 54 IMA LC cases. MUC5AC was positively expressed in 50 (93%), MUC6 in 38 (70%), and αGlcNAc in 19 (35%). Each expression level was scored from 0 to 3. The αGlcNAc expression score was significantly decreased relative to MUC6 (P < 0.001). Interestingly, disease-free survival was significantly higher in MUC6-positive than MUC6-negative cases based on the log-rank test (P = 0.021). For in vitro analysis, we ectopically expressed MUC6 in A549 cells, derived from LC and harboring a KRAS mutation. MUC6-expressing A549 cells showed significantly lower proliferation, motility, and invasiveness than control cells. Finally, F-actin staining in MUC6-expressing cells revealed a decrease or loss of filopodia associated with decreased levels of FSCN transcripts, which encodes an actin-bundling protein fascin1 necessary for cell migration. We conclude that MUC6 expression is a preferable prognostic biomarker in IMA LC.

Glycosylation of MUC6 by α1,4-linked N-acetylglucosamine enhances suppression of pancreatic cancer malignancy

Biomarkers for early diagnosis of pancreatic cancer are greatly needed, as the high fatality of this cancer is in part due to delayed detection. α1,4‐linked N‐acetylglucosamine (αGlcNAc), a unique O‐glycan specific to gastric gland mucus, is biosynthesized by α1,4‐N‐acetylglucosaminyltransferase (α4GnT) and primarily bound at the terminal glycosylated residue to scaffold protein MUC6. We previously reported that αGlcNAc expression decreases at early stages of neoplastic pancreatic lesions, followed by decreased MUC6 expression, although functional effects of these outcomes were unknown. Here, we ectopically expressed α4GnT, the αGlcNAc biosynthetic enzyme, together with MUC6 in the human pancreatic cancer cell lines MIA PaCa‐2 and PANC‐1, neither of which expresses α4GnT and MUC6. We observed significantly suppressed proliferation in both lines following coexpression of α4GnT and MUC6. Moreover, cellular motility decreased following MUC6 ectopic expression, an effect enhanced by cotransduction with α4GnT. MUC6 expression also attenuated invasiveness of both lines relative to controls, and this effect was also enhanced by additional α4GnT expression. We found αGlcNAc‐bound MUC6 formed a complex with trefoil factor 2. Furthermore, analysis of survival curves of patients with pancreatic ductal adenocarcinoma using a gene expression database showed that samples marked by higher A4GNT or MUC6 mRNA levels were associated with relatively favorable prognosis. These results strongly suggest that αGlcNAc and MUC6 function as tumor suppressors in pancreatic cancer and that decreased expression of both may serve as a biomarker of tumor progression to pancreatic cancer.

Decreased Gastric Gland Mucin-specific O-glycans Are Involved in the Progression of Ovarian Primary Mucinous Tumours

Ovarian primary mucinous tumours (OPMTs) show an adenoma–borderline–carcinoma sequence with gastrointestinal metaplasia. Gastric gland mucin-specific O-glycans are unique with an α1,4-linked N-acetylglucosamine (αGlcNAc) residue attached to mucin 6 (MUC6). Although αGlcNAc is expected to be expressed in OPMTs, the relationship between αGlcNAc expression and OPMT progression remains unknown. Here, we analysed 104 areas of benign mucinous tumours (benign), 55 areas of borderline mucinous tumours (borderline), and 18 areas of malignant mucinous tumours (malignant) to investigate the expression patterns of αGlcNAc, mucin 2 (MUC2), mucin 5AC (MUC5AC), and MUC6 during the progression of OPMT from benign to malignant. MUC5AC expression was observed in all areas. The frequencies of MUC6- and αGlcNAc-positive areas were decreased with tumour progression. In particular, the decrease in αGlcNAc-positive areas was remarkable. Furthermore, αGlcNAc expression was lower than MUC6 expression at all grades (benign, p < 0.0001; borderline, p = 0.0014; malignant, p = 0.0039). Conversely, there was no difference in the expression frequency or level of MUC2 among the three grades. These results suggest that decreased expression of αGlcNAc relative to MUC6 occurs early in tumour development and marks the initiation of OPMT progression.

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

Gastric-type carcinoma (GAS) is the most common human papilloma virus-independent endocervical adenocarcinoma (ECA), characterized by an aggressive behavior. Trefoil factor 2 (TFF2) is a mucin-associated peptide expressed in normal gastric but not endocervical glands. This study was carried out to investigate whether TFF2 could be a surrogate marker to separate GAS from other types of ECA. ECAs from 9 international institutions were reviewed for consensus histotype. Of them, expression of TFF2 was immunohistochemically examined compared with that of HIK1083, using whole sections of 50 ECAs (10 GASs and 40 non-GASs) and 179 ECAs (24 GASs and 155 non-GASs) with tissue microarrays (TMAs). TMAs were assessed to simulate assessment of immunohistochemical stains in small biopsies. Both markers were similarly scored, and any cytoplasmic/membranous staining of >5% of tumor cells was considered positive. Of 50 ECAs with whole sections, TFF2 was significantly more frequently expressed in GASs (8/10) compared with non-GASs (5/40) (P<0.01). In 179 ECAs with TMAs, TFF2 was also significantly more frequently expressed in GASs (7/24) compared with non-GASs (4/155) (P<0.01). There was no significant difference in specificity among the 2 markers. Double positivity for TFF2 and HIK1083 in ECAs was highly specific in separating GASs from non-GAS (P<0.01). A significantly smaller percentage of GASs were TFF2 positive in TMAs than in whole sections (P<0.01). Our results suggest that TFF2 is a promising marker, along with HIK1083, to confirm a diagnosis of GAS. This marker may be negative in small biopsies, indicating the necessity of using other exclusionary markers in combination with rigorous morphologic review and extensive sampling in resection specimens.

Cytomorphologic Features of Gastric-Type Endocervical Adenocarcinoma in Liquid-Based Preparations

OBJECTIVE

Gastric-type endocervical adenocarcinoma (GAS) is a recently described, uncommon, and aggressive tumor with distinct morphologic features and HPV-independent etiology. Data on GAS in liquid-based cytology (LBC) Papanicolaou (Pap) test preparations from a North American patient population are scant. We systematically assessed the cytomorphologic characteristics of GAS in LBC from patients in Ontario and examined if glandular cell nuclear area could represent a readily assessable feature which may aid in GAS detection.

STUDY DESIGN

Pap test slides preceding the diagnosis of GAS were retrieved locally or requested from outside laboratories. A structured review of 15 cytomorphologic features was performed using the available LBC Pap test slides of GAS and a set of usual-type endocervical adenocarcinomas (UEA). Morphometry of the glandular cell nuclear area was performed, and normalized values were compared to UEA and benign endocervical cells.

RESULTS

At least 1 Pap test (5 ThinPrep®, 11 SurePath®, and 1 direct smear) was available for 14 patients. Original LBC Pap test diagnoses were negative for intraepithelial lesion or malignancy (NILM) (7), adenocarcinoma/carcinoma (6), atypical glandular cells (2), and adenocarcinoma in situ (1). Review detected abnormal glandular cells in 6/7 NILM cases. Honeycomb-like sheets, nuclear enlargement, and microvesicular cytoplasm were the single most common architectural, nuclear, and cytoplasmic features, respectively. Microvesicular cytoplasm (100 vs. 17%), honeycomb-like sheets (87 vs. 8%), prominent nucleoli (93 vs. 25%), and anisonucleosis (93 vs. 50%) were most discriminatory for GAS versus UEA, respectively. Yellow mucin, intranuclear cytoplasmic pseudoinclusions, and goblet/Paneth-like cells were uncommon, but unique for GAS. Glandular cell nuclear area normalized to neutrophils was found to be significantly increased in GAS compared to benign endocervical cells.

CONCLUSIONS

GAS is under-recognized and may mimic reactive endocervical cells. Awareness of the tumor type and its cytomorphology is critical for early detection. Identification of glandular cells with uniform nuclear enlargement in conjunction with any of the other cytologic features may help avoid false-negative Pap results. Neutrophils may serve as convenient size reference and visual aid.

Decreased alpha-1,4-linked N-acetylglucosamine glycosylation in biliary tract cancer progression from biliary intraepithelial neoplasia to invasive adenocarcinoma

Biliary tract cancer (BTC) is typically lethal due to the difficulty of early stage diagnosis. Thus, novel biomarkers of BTC precursors are necessary. Biliary intraepithelial neoplasia (BilIN) is a major precursor of BTC and is classified as low or high grade based on cell atypia. In normal gastric mucosa, gastric gland mucin‐specific O‐glycans are unique in having α1,4‐linked N‐acetylglucosamine (αGlcNAc) attached to MUC6. Previously, we reported that αGlcNAc functions as a tumor suppressor of differentiated‐type gastric adenocarcinoma and that decreased αGlcNAc glycosylation on MUC6 in gastric, pancreatic, and uterine cervical neoplasms occurs in cancer as well as in their precursor lesions. However, αGlcNAc and MUC6 expression patterns in biliary tract neoplasms have remained unclear. Here, we analyzed MUC5AC, MUC6, and αGlcNAc expression status in 51 BTC cases and compared the expression of each with progression from low‐grade BilIN to invasive adenocarcinoma (IAC). The frequency of αGlcNAc‐positive and MUC6‐positive lesions decreased with tumor progression. When we compared each marker’s expression level with tumor progression, we found that the MUC6 expression score in IAC was significantly lower than in low‐grade or high‐grade BilIN (P < 0.001 or P < 0.01, respectively). However, the αGlcNAc expression score was low irrespective of histological grade, and also lower than that of MUC6 across all histological grades (P < 0.001 for low‐grade and high‐grade BilIN, and P < 0.01 for IAC). These results suggest that decreased expression of αGlcNAc relative to MUC6 marks the initiation of BTC progression.

A combination of cytokeratin 5/6, p63, p40 and MUC5AC are useful for distinguishing squamous cell carcinoma from adenocarcinoma of the cervix

Purpose

Squamous cell carcinomas and adenocarcinomas are the most common types of cervical cancer. Compared to squamous cell carcinomas, adenocarcinomas are more common in younger women and have a poorer prognosis. Yet, so far, no useful biomarkers have been developed for these two types of cancer. In the following study, we examined the combination of cytokeratin 5/6, p63, p40 and MUC5AC for distinguishing squamous cell carcinoma (SCC) from adenocarcinoma of the cervix (AEC).

Materials and methods

A total of 101 SCC and 108 AEC were collected. Immunohistochemical analyses were conducted to determine the expression of CK5/6, p63, p40, CK7 and MUC5AC. One pathologist who was blinded to the patient’s clinical and pathological data interpreted the staining results.

Results

MUC5AC and CK7 were detected in 81.48 and 82.41% of AEC cases compared to 9.9 and 49.50% of SCC cases (P < 0.05); the specificity of MUC5AC was higher than that of CK7 in AEC (P < 0.05). The sensitivity of MUC5AC combined with p40 or p63 was similar to that of CK7, but the specificity was slightly higher than that of CK7 in AEC. Moreover, the expression of MUC5AC was correlated with the degree of tumor differentiation in adenocarcinomas (P = 0.036) and was not related to the prognosis of cervical adenocarcinoma and subtypes.

Conclusions

MUC5AC may be useful as a biomarker for differential diagnoses between squamous carcinoma and adenocarcinoma of the cervix.

Diffuse MIST1 expression and decreased α1,4-linked N-acetylglucosamine (αGlcNAc) glycosylation on MUC6 are distinct hallmarks for gastric neoplasms showing oxyntic gland differentiation

AIMS

Gastric neoplasms showing oxyntic gland differentiation (GAOGs) constitute a gastric neoplasm subtype that shows low atypia, thus similar to non-neoplastic gastric oxyntic glands. Therefore, their diagnosis in biopsy specimens is difficult. GAOGs were first described in 2007, and introduced in the latest World Health Organization classification book as gastric adenocarcinoma of the fundic gland type (GA-FG) and oxyntic gland adenoma. Previously, we assessed α1,4-linked N-acetylglucosamine (αGlcNAc) residues attached to the MUC6 scaffold in gastric neoplasms, and observed decreased αGlcNAc glycosylation in both differentiated-type gastric cancer and high-grade pyloric gland adenoma (PGA), a gastric cancer precursor. GA-FG and PGA often harbour the same mutations. However, the αGlcNAc status in GAOGs remained unknown. To elucidate αGlcNAc expression in GAOGs, we performed the study.

METHODS AND RESULTS

We assessed the expression of αGlcNAc; the mucin markers MUC6, MUC5AC, and MUC2; the gastric gland cell markers MIST1, pepsinogen 1 (PG1), H/K-ATPase and chromogranin-A (CGA); and the proliferation marker Ki67 in 13 GAOG lesions. All 13 (100%) were MUC6-positive, whereas 10 (76.2%) were αGlcNAc-negative. Moreover, all 13 (100%) were MIST1- and PG1-positive, three (23.1%) were MUC5AC-positive, four (30.8%) were H/K-ATPase-positive, and one (7.7%) was CGA-positive.

CONCLUSIONS

GAOGs frequently lost αGlcNAc residues on MUC6, but expressed the gastric gland progenitor marker MIST1 and aberrantly expressed various types of gastric gland cell lineage marker, suggestive of immature differentiation to gastric gland cells. Thus, diffuse MIST1 positivity and decreased αGlcNAc glycosylation on MUC6-positive cells could serve as important biomarkers for the histopathological diagnosis of GAOG.

αGlcNAc and its catalyst α4GnT are diagnostic and prognostic markers in uterine cervical tumor, gastric type

Cervical adenocarcinoma, gastric type (GAS) is not associated with human papilloma virus (HPV) infection. GAS patients prognoses are significantly worse compared with cervical adenocarcinoma associated with HPV infection, as their tumors exhibit resistance to conventional chemotherapy and radiotherapy. GAS is often associated with lobular endocervical glandular hyperplasia (LEGH), which is regarded as a precursor to GAS in the latest WHO classification. Recently, we reported that a decrease in expression of terminal α1,4-linked N-acetylglucosamine (αGlcNAc) relative to that of MUC6 was already apparent in atypical LEGH in the LEGH-GAS sequence. Here, we analyzed expression of α1,4-N-acetylglucosaminyltransferase (α4GnT), the sole enzyme catalyzing αGlcNAc biosynthesis, and that of αGlcNAc and MUC6 in cases representing non-neoplastic endocervical gland (NNEG) (11 cases), LEGH (26 cases) and GAS (12 cases). α4GnT protein was detected in a "dot-like" pattern, indicating localization in the Golgi apparatus in all 26 LEGH cases and 5 of 12 GAS cases. α4GnT- and αGlcNAc-positive cells largely overlapped, suggesting that α4GnT gene expression regulates αGlcNAc biosynthesis. Interestingly, all NNEG cases were negative for α4GnT and αGlcNAc expression, but 7 of 11 NNEG and all LEGH cases were MUC6-positive. In GAS cases, patients whose tumors were α4GnT- and αGlcNAc-positive had more favorable prognosis than others. Multivariate analysis revealed that positive expressions of α4GnT and αGlcNAc were independent prognostic indicators. These results indicate that α4GnT and αGlcNAc could serve as useful markers not only to distinguish LEGH from NNEG but to evaluate prognoses of GAS patients.

Trefoil factor family 2 protein: a potential immunohistochemical marker for aiding diagnosis of lobular endocervical glandular hyperplasia and gastric-type adenocarcinoma of the uterine cervix

Gastric-type adenocarcinoma (GA) is an aggressive subtype of cancer of the uterine cervix. Several immunohistochemical markers for gastric mucins, such as mucin 6 (MUC6) and N-acetylglucosamine α1 → 4galactose → R (αGlcNAc-R), which is recognized by HIK1083 antibody, have been introduced for diagnosis of GA and lobular endocervical glandular hyperplasia (LEGH). However, MUC6 is also expressed in normal endocervical glands and HIK1083 antibody has limited availability. Trefoil factor family 2 protein (TFF2) is secreted by gastric, but not normal endocervical glands. Here, we evaluated TFF2 immunostaining for detection of a gastric immunophenotype in endocervical glandular lesions. We compared TFF2, αGlcNAc-R, and MUC6 expression in 103 endocervical glandular lesions: LEGH (n = 23), adenocarcinoma in situ/microinvasive adenocarcinoma (AIS-MIA) (n = 29), and invasive adenocarcinoma (usual type [UA], n = 26; GA, n = 11; intestinal type [IA], n = 2; signet ring cell type [Sig], n = 2; and mucinous adenocarcinoma not otherwise specified [NOS], n = 10). TFF2 and αGlcNAc-R expression was completely concordant in each subtype: LEGH (100%), AIS-MIA (44.8%), UA (26.9%), GA (90.9%), IA (100%), Sig (0%), and NOS (20%). TFF2 staining scores were significantly correlated with those of αGlcNAc-R in these lesions. TFF2 and αGlcNAc-R immunoreactivity was present in cytoplasmic mucins and luminal secretions. TFF2 and αGlcNAc-R were not expressed in the normal endocervical glands. MUC6 was frequently expressed in normal endocervical glands and endocervical glandular lesions. Endocervical adenocarcinomas sometimes stained only for MUC6. TFF2 is a promising immunohistochemical marker and its identification in uterine cervical secretion is a potentially useful diagnostic test for endocervical glandular lesions with gastric differentiation.