Calponin and MUC6 complement inhibin as diagnostic immunomarkers of serous cystadenoma in endoscopic ultrasound-guided aspiration/biopsy specimens

AIMS

Because serous cystadenoma (SCA) does not usually require excision, it is critical to distinguish it from differential diagnoses which do, especially neuroendocrine tumour (NET). The gold standard for diagnosing SCA is assessment of endoscopic ultrasound-guided fine needle aspiration/biopsy (EUS-FNAB) material. Inhibin immunohistochemistry aids this assessment, but such positivity is not absolutely sensitive or specific to SCA. The following is the largest known study of SCA EUS-FNAB specimens and the first to compare four potential SCA immunomarkers between themselves and inhibin, compared against NET.

METHODS AND RESULTS

Immunohistochemistry for calponin, mucin 6 (MUC6), glucose transporter 1 (GLUT1) and vascular endothelial growth factor A (VEGFA) was performed on 30 EUS-FNAB and three resection specimens of SCA and 32 EUS-FNAB specimens of NET. GLUT1 and VEGFA were suboptimal as diagnostic immunomarkers of SCA, being expressed by 10 and 44% of NETs, respectively. Further, their expression by cellular constituents of blood which often contaminate EUS-FNAB specimens hampered identification of neoplastic cells, especially in hypocellular samples. While 19% of NETs showed nuclear MUC6 positivity, cytoplasmic expression of the protein showed 100% specificity and sensitivity as an SCA marker. However, assessing MUC6 in EUS-FNAB specimens must also consider the protein's focal expression in physiological pancreatic, gastric or duodenal tissues, which can contaminate these specimens. Calponin was less sensitive (71% versus 100%) but more specific (100% versus 91%) than inhibin, although easier to assess in EUS-FNAB specimens than MUC6.

CONCLUSIONS

Of the four potential immunomarkers of SCA suggested by the existing literature, calponin and MUC6 are useful complementary studies to inhibin for application to EUS-FNAB specimens.

The combined application of urinary liquid-based cytology with fluorescence in situ hybridization and p16/Ki-67 dual immunostaining is valuable for improving the early diagnosis of upper tract urothelial carcinomas

OBJECTIVES

To evaluate the diagnostic values of urine liquid-based cytology (LBC), fluorescence in situ hybridization (FISH), and p16/Ki-67 dual immunostaining in the detection of upper tract urothelial carcinomas (UTUCs).

METHODS

Sixty-one patients with UTUCs were retrospectively analyzed. All patients were diagnosed both by urine cytology and by FISH, and histologically confirmed as UTUCs. Thirty-two patients had been stained with p16/Ki-67 dual labeling.

RESULTS

The sensitivities for low-grade UTUCs (LGUTUCs) and high-grade UTUCs (HGUTUCs) were 33.3% and 67.4% by LBC, 60% and 69.6% by FISH, and 12.5% and 66.7% by p16/Ki-67 dual labeling, respectively.

CONCLUSIONS

Our results indicated that LBC was more suitable to identify HGUTUCs, FISH was highly valuable for predicting LGUTUCs, and p16/Ki-67 dual labeling was useful for distinguishing HGUTUCs from LGUTUCs. The combined application of these methods may improve the sensitivity or accuracy in the detection or diagnosis of UTUCs.