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.

卵巢原发性黏液性肿瘤 (OPMT) 显示腺瘤 - 交界 - 癌序列，伴有胃肠道化生。胃腺粘蛋白特异性O-聚糖是独特的，具有 α1,4 连接的N-乙酰氨基葡萄糖 (αGlcNAc) 残基连接到粘蛋白 6 (MUC6)。尽管预计 αGlcNAc 会在 OPMT 中表达，但 αGlcNAc 表达与 OPMT 进展之间的关系仍然未知。在这里，我们分析了 104 个良性粘液性肿瘤（良性）、55 个交界性粘液性肿瘤（边界）和 18 个恶性粘液性肿瘤（恶性）区域，以研究 αGlcNAc、粘蛋白 2（MUC2）、粘蛋白 5AC 的表达模式(MUC5AC) 和 MUC6 在 OPMT 从良性到恶性的进展过程中。在所有区域均观察到 MUC5AC 表达。MUC6-和αGlcNAc-阳性区域的频率随着肿瘤进展而降低。特别是，αGlcNAc 阳性区域的减少是显着的。此外，αGlcNAc 表达在所有级别都低于 MUC6 表达（良性，p< 0.0001；临界值，p = 0.0014；恶性，p = 0.0039）。相反，三个等级之间MUC2的表达频率或水平没有差异。这些结果表明，αGlcNAc 相对于 MUC6 的表达降低发生在肿瘤发展的早期，并标志着 OPMT 进展的开始。