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Year : 2020  |  Volume : 63  |  Issue : 1  |  Page : 49-52
Expression of alpha-methylacyl-CoA racemase in vaginal gastric-type adenocarcinoma and uterine clear cell carcinoma

Department of Pathology, Hubei Maternal and Child Health Hospital of Hubei Province, Wuluo Road, Wuhan, China

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Date of Web Publication31-Jan-2020


Background: Alpha-methylacyl-coenzyme A racemase (AMACR, P504S) is a commonly used marker in immunohistochemical diagnosis of prostate cancer. Recent studies identified P504S markers of the clear cell histotype in the ovary and/or endometrium. Gastric-type adenocarcinoma (GAS) is difficult to diagnose histologically, particularly when there is crossover with clear cell carcinoma (CCC). However, the significance of P504S for differentially diagnosing GAS and CCC is unclear. Aim: To evaluate P504S as a potential diagnostic marker of GAS and CCC. Settings and Design: We analyzed P504S expression in 48 cervical carcinomas (32 GAS and 16 CCC), as well as the expression of other markers including hepatocyte nuclear factor-1 beta (HNF-1β) and NapsinA. Material and Methods: The expression differences of HNF-1β, NapsinA, and P504S in GAS and CCC were detected by immunohistochemistry. Immunohistochemical histoscores based on the intensity and extent of staining were calculated. Results: The positive rates of HNF-1β in GAS and CCC were 90.32% and 75%, respectively. (χ2 = 2.251, P = 0.663). The positive rates of NapsinA in GAS and CCC were 19.36% and 81.25%, respectively. (χ2 = 47.332, P < 0.01). The positive rates of P504S in GAS and CCC were 16.13% and 81.25%, respectively. (χ2 = 41.420, P < 0.01). HNF-1β was frequently expressed in GAS and CCC, while NapsinA and P504S were frequently expressed in CCC, and reduced or lost in GAS. Conclusion: NapsinA and P504S can be used to differentiate between GAS and CCC.

Keywords: Alpha-methylacyl-CoA racemase, clear cell carcinoma, gastric-type adenocarcinoma, hepatocyte nuclear factor-1 beta, NapsinA, P504S

How to cite this article:
Hu J, Lu Y, Tang N, Li L, Guo P, Zhang Y. Expression of alpha-methylacyl-CoA racemase in vaginal gastric-type adenocarcinoma and uterine clear cell carcinoma. Indian J Pathol Microbiol 2020;63:49-52

How to cite this URL:
Hu J, Lu Y, Tang N, Li L, Guo P, Zhang Y. Expression of alpha-methylacyl-CoA racemase in vaginal gastric-type adenocarcinoma and uterine clear cell carcinoma. Indian J Pathol Microbiol [serial online] 2020 [cited 2023 Jan 30];63:49-52. Available from:

   Introduction Top

Cervical cancer is a common gynecological malignancy, and persistent infection with high-risk human papillomavirus (hrHPV) is considered the most important cause of cervical cancer.[1] Nearly all squamous cell carcinoma cases are causally related to persistent infection (high-risk), while approximately 15% of cervical adenocarcinoma cases are not associated with HPV infection; the most frequent is gastric-type adenocarcinoma (GAS).[2] GAS is a rare, specific type of cervical adenocarcinoma that may originate from gastric metaplasia or  Peutz-Jeghers syndrome More Details, and is associated with lobular endocervical glandular hyperplasia, showing a gastric morphology and immunophenotype.[3],[4] GAS is characterized by invasion and metastasis, which can occur in non-HPV-related cases, and shows worse prognosis than typical HPV-associated cervical adenocarcinoma.[5],[6] The morphological and immunohistochemical characteristics of GAS have been confirmed in recent years. This disease is rare and difficult to diagnose because the histological manifestations of GAS are mild under hematoxylin and eosin (HE) staining of the benign, premalignant, and malignant lesions.[7],[8] Particularly, the cytoplasm of GAS cells is typically abundant and clear or eosinophilic. Crossover with clear cell carcinoma (CCC) accounts for 1.8–6.0% of cervical adenocarcinoma cases and is not associated with HPV infection. Therefore, local GAS is prone to misdiagnosis and missed diagnosis. This enables GAS to progress in most patients, and the disease is often advanced at diagnosis. Thus, early detection and identification of GAS are clinically important.

The three classic immunohistochemical markers HNF-1β, NapsinA, and alpha-methyl acyl-coenzyme A racemase (P504S) are useful for confirming the diagnosis of CCC in the ovaries and endometrium. HNF-1β is not useful to distinguish GAS and CCC, whereas NapsinA is more valuable for differential diagnosis.[9] However, no studies have evaluated P504S for differential diagnosis of GAS and CCC. In this study, we screened 48 cases of cervical adenocarcinoma and evaluated P504S as a potential diagnostic marker of GAS and CCC.

   Materials and Methods Top

Case selection

Forty-eight patients with cervical adenocarcinoma treated at Hubei Provincial Maternal and Child Health Hospital from May 2005 to February 2019 were selected, including 32 cases of GAS with an average age of 36 years and 16 cases of CCC with an average age of 38 years. All cases were confirmed by two senior pathologists, and no patients were administered radiotherapy or chemotherapy before surgery. Patients with serious complications such as heart disease, diabetes, and mental illness were excluded from this study. This study was approved by the ethics committee of Hubei Maternal and Child Health Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology. All selected patients signed informed consent forms.

Immunohistochemistry detection

All biopsy specimens were processed in the molecular laboratory of pathology in our hospital. The specimens were fixed with 10% neutral formalin, dehydrated in an STP420ES dehydrator (Thermo Fisher Scientific, Waltham, MA, USA), and sectioned after paraffin embedding. Sections were cut at 3–4 μm thickness, stained with HE, and confirmed to contain foci of GAS or CCC. The EnVision method of immunohistochemistry was used to detect the antigen; the antigen repair solution was citrate buffer (pH 6.0). Immunohistochemical operation was carried out on the Roche automatic immunohistochemical staining instrument (Basel, Switzerland), and the operation steps were conducted in accordance with the manufacturer's instructions. In cases of >1 block, the block with the highest density of glands involving GAS or CCC was selected. For immunohistochemistry analysis, whole-mount tissue sections were used for DAB color rendering, hematoxylin contrast staining, microscopic observation. Mouse monoclonal antibodies against human HNF-1β, NapsinA, and P504S were procured from Gene Tech (Shanghai) Company Limited and the primary antibody was used at the concentration provided. Known positive sections of HNF-1β, NapsinA, and P504S were used as positive controls, and phosphate-buffered saline was used as negative control rather than primary antibody.

Interpretation of immunohistochemical staining results

For HNF-1β, brown staining of the nucleus was considered as a positive result. For NapsinA and P504S, any granular brown staining in the cell cytoplasm was considered as a positive result. The intensity of staining was scored as negative (0), weak (1+), moderate (2+), and strong (3+). The extent of staining of was assessed and classified as negative (0), <50% (1+), and >50% (2+). By multiplying the intensity and extent scores, a histoscore ranging from 0 to 6 was generated. For example, if a tumor showed strong staining in >50% of cells, the score was 3 × 2 = 6. For HNF-1β, cytoplasmic staining alone or in association with nuclear staining was not scored. As the cell types in cervical adenocarcinoma may either be clear or nonclear, the expression of HNF-1β, NapsinA, and P504S relative to these cell types was also assessed by direct correlation with the same glands on the corresponding HE slides.

Statistical analysis

By using the Chi-square test and Fisher's exact probability test, analyses were performed using SPSS version 19 software (SPSS, Inc., Chicago, IL, USA). P < 0.05 was considered as statistically significant in all analyses.

   Results Top

Vaginal GAS

All 48 patients with GAS had symptoms of irregular vaginal bleeding, contact bleeding, and massive vaginal discharge. Some patients were treated for pelvic pain and urinary obstruction. Tumor cells were voluminous clear or pale eosinophilic cytoplasm with distinct cell borders [Figure 1]a.
Figure 1: Similar morphologic appearance in cervical GAS (a) and CCC (b). GAS: Gastric-type adenocarcinomas; CCC: Clear cell carcinoma

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Uterine CCC

Sixteen patients with CCC of the cervix showed symptoms of irregular vaginal bleeding, contact bleeding, and massive vaginal discharge. The tumor was composed of polygonal or spiky-like cells with abundant and clear cytoplasm and eosinophilic cytoplasm. The cells were arranged in papillary, tubular, and solid lamellar structures. Cells comprising the tumor contained abundant clear cytoplasm, with prominent nuclei that were hyperchromatic and pleomorphic [Figure 1]b.

Immunohistochemical results

The immunohistochemical results are presented in [Table 1]. HNF-1β, NapsinA, and P504S showed positive staining in 28 (90.32%), 6 (19.36%), and 5 (16.13%) of 32 cases, respectively, in GAS. Twelve of the 16 CCC cases were positive for HNF-1β (75%) and 13 were positive for NapsinA (81.25%). P504S showed the same expression level as NapsinA. Morphologic features of GAS are illustrated in [Figure 1] and immunohistochemistry results are shown in [Figure 2].
Table 1: HNF-1β, Napsin A, and P504S expression in GAS and CCC

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Figure 2: (a-f) Expression of HNF-1β in GAS (a) and CCC (b); Expression of NapsinA in GAS (c) and CCC (d); Expression of P504S in GAS (e) and CCC (f)

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   Discussion Top

Nearly all cervical cancers are associated with HPV infection. In recent years, with the wide implementation of cervical cancer screening and application of the HPV vaccine, the incidence and mortality of squamous cell carcinoma have decreased significantly, while the incidence rate of cervical adenocarcinoma continues to increase.[10],[11] Cytology combined with HPV testing is the primary means of screening for cervical cancer. Approximately 10% of both common and rare cervical adenocarcinomas are unrelated to HPV infection. Among the most common is GAS. Holl et al.[2] studied data from 614 cervical patients from 17 European countries. Cervical adenocarcinoma without HPV infection mainly included GAS, CCC, mesonephric adenocarcinoma, and serous carcinoma.[3],[12]

The typical features of GAS are epithelial cells that are columnar with basally located nuclei and abundant apical eosinophilic cytoplasm. The developing spectrum of gastric-type cervical glandular revealed that well-differentiated areas showed minimal deviation from adenocarcinoma, while poorly differentiated lesions had more nuclear atypia and solid growth.[7] The cells showed clear or eosinophilic cytoplasm and prominent cell boundaries, which is a typical feature of CCC, and nuclear anisotropy is apparent, the nucleolus was distinctly pleomorphic and unequal in size, and nuclear division was common. The post-neoadjuvant therapy hysterectomy specimen showed tumor cells with clear cytoplasm and hyperchromatic nuclei with irregular contours, which mimicked CCC.[13] In general, GAS and CCC are easily distinguished when tumor cells have typical characteristics. However, it is difficult to distinguish these cells when atypical conditions are observed, particularly when using small biopsy specimens.

The immunohistochemical markers HNF-1β, NapsinA, and P504S are useful for confirming a diagnosis of CCC in the ovaries and endometrium.[13],[14] HNF-1β is a widely used immunohistochemical marker for diagnosing CCC in the ovary, and it has been reported that the antibody can be used as an immunohistochemical marker for diagnosing cervical adenocarcinoma.[14] We found that the positive rate of HNF-1β in CCC was 75% and that in GAS was up to 90.32%. This agrees with previously reported results.[9] NapsinA is an aspartic acid protease, which is widely distributed in normal lung and kidney tissues, and is an immunologic marker mainly used for diagnosing primary lung cancer.[15] The previous studies showed that NapsinA is valuable for the diagnosis and differentiation of CCC.[16] Earlier reports suggested that HNF-1β is a specific marker for the diagnosis of CCC. However, because of its low specificity, HNF-1β alone is not considered as useful for diagnosing CCC, whereas Napsin A is a more specific marker.[17] In this study, the positive rate of HNF-1β in GAS was 90.32% and that in CCC was 75%; this difference was not significant (P > 0.05). These results suggest that HNF-1β is not a good diagnostic marker. The positive rates of NapsinA in GAS and CCC were 19.36% and 81.25%, respectively (χ2 = 47.332, P < 0.01). The expression difference was significant, which agrees with the results of Talia et al.[9] In addition, positive expression of NapsinA in CCC was mostly focal, while expression of HNF-1β was diffuse. The P504S antibody was originally used for immunohistochemical diagnosis of prostate cancer by Jing et al. This antibody was thought to be a highly sensitive and specific marker of prostate cancer.[18] Recently, the enzyme P504S as a marker of the clear cell histotype has been reported in the ovary and/or endometrium. Studies have shown that P504S is expressed in 70–75% of uterine and ovarian CCC cases.[19] In this study, the positive rates of P504S in GAS and CCC were 16.13% and 81.25%, respectively (χ2 = 41.420, P < 0.01). The expression difference was significant, which was consistent with the data for NapsinA. This suggests that P504S plays an important role in the differential diagnosis of GAS and CCC.

   Conclusion Top

In summary, we highlighted the potential for diagnostic confusion between cervicovaginal GAS and CCC and showed that the three most commonly utilized markers of CCC may be positive in GAS, with HNF-1β much more commonly expressed than NapsinA and P504S. Therefore, under conditions of diagnostic uncertainty, NapsinA and P504S are more valuable than HNF-1β for differentiating GAS and CCC. Careful histologic examination will enable accurate diagnosis. However, the number of the cases in this study was limited; thus, using P504S as a marker for pathological differential diagnosis should be further evaluated.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

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Holl K, Nowakowski AM, Powell N, McCluggage WG, Pirog EC, Collas De Souza S, et al. Human papillomavirus prevalence and type-distribution in cervical glandular neoplasias: Results from a European multinational epidemiological study. Int J Cancer 2015;137:2858-68.  Back to cited text no. 2
Tsuda H, Mikami Y, Kaku T, Akiyama F, Hasegawa T, Okada S, et al. Interobserver variation in the diagnosis of adenoma malignum (minimal deviation adenocarcinoma) of the uterine cervix. Pathol Int 2003;53:440-9.  Back to cited text no. 3
Sugihara T, Nakagawa S, Sasajima Y, Matsumoto Y, Takeshita S, Ayabe T. Case of minimal deviation adenocarcinoma: Possible clinical link to lobular endocervical glandular hyperplasia as its origin. J Obstet Gynaecol Res 2015;41:483-7.  Back to cited text no. 4
Chen YP, Ho SP, Liou WS, Chen CJ. Minimal deviation adenocarcinoma of the uterine cervix. Taiwan J Obstet Gynecol 2015;54:447-9.  Back to cited text no. 5
Mikami Y, McCluggage WG. Endocervical glandular lesions exhibiting gastric differentiation: An emerging spectrum of benign, premalignant, and malignant lesions. Adv Anat Pathol 2013;20:227-37.  Back to cited text no. 6
Talia KL, McCluggage WG. The developing spectrum of gastric-type cervical glandular lesions. Pathology 2018;50:122-33.  Back to cited text no. 7
McCluggage WG. Recent developments in non-HPV-related adenocarcinomas of the lower female genital tract and their precursors. Adv Anat Pathol 2016;23:58-69.  Back to cited text no. 8
Talia KL, Wong RW, McCluggage WG. Expression of markers of mullerian clear cell carcinoma in primary cervical and vaginal gastric-type adenocarcinomas. Int J Gynecol Pathol 2019;38:276-82.  Back to cited text no. 9
van der Horst J, Siebers AG, Bulten J, Massuger LF, de Kok IM. Increasing incidence of invasive and in situ cervical adenocarcinoma in the Netherlands during 2004-2013. Cancer Med 2017;6:416-23.  Back to cited text no. 10
Oh CM, Jung KW, Won YJ, Shin A, Kong HJ, Jun JK, et al. Trends in the incidence of in situ and invasive cervical cancer by age group and histological type in Korea from 1993 to 2009. PloS One 2013;8:e72012.  Back to cited text no. 11
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Zhang Y, Liang L, Euscher ED, Liu J, Ramalingam P. Gastric-type mucinous adenocarcinoma of the uterine cervix with neoadjuvant therapy mimicking clear cell carcinoma. Int J Clin Exp Pathol 2015;8:11798-803.  Back to cited text no. 13
Nemejcova K, Cibula D, Dundr P. Expression of HNF-1beta in cervical carcinomas: An immunohistochemical study of 155 cases. Diagn Pathol 2015;10:8.  Back to cited text no. 14
Zhang P, Han YP, Huang L, Li Q, Ma DL. Value of napsin A and thyroid transcription factor-1 in the identification of primary lung adenocarcinoma. Oncol Lett 2010;1:899-903.  Back to cited text no. 15
Kandalaft PL, Gown AM, Isacson C. The lung-restricted marker napsin A is highly expressed in clear cell carcinomas of the ovary. Am J Clin Pathol 2014;142:830-6.  Back to cited text no. 16
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Jiang Z, Woda BA, Rock KL, Xu Y, Savas L, Khan A, et al. P504S: A new molecular marker for the detection of prostate carcinoma. Am J Surg Pathol 2001;25:1397-404.  Back to cited text no. 18
Fadare O, Parkash V, Gwin K, Hanley KZ, Jarboe EA, Liang SX, et al. Utility of alpha-methylacyl-coenzyme-A racemase (p504s) immunohistochemistry in distinguishing endometrial clear cell carcinomas from serous and endometrioid carcinomas. Hum Pathol 2013;44:2814-21.  Back to cited text no. 19

Correspondence Address:
Junbo Hu
Department of Pathology, Maternal and Child Health Hospital of Hubei Province, 745 Wuluo Road - 430 070 Wuhan,
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJPM.IJPM_525_19

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