lewis-x-antigen and Adenocarcinoma--Clear-Cell

Yolk sac tumors (YSTs) have a variety of morphologic patterns, some of which can resemble either endometrioid adenocarcinoma (EAC) or clear cell carcinoma (CCC). Immunohistochemical staining for alpha-fetoprotein (AFP) is usually only focal and thus is not always helpful in the diagnosis of YST, and pancytokeratin (CK) is expressed by all three tumors. We studied a battery of immunohistochemical markers with specific attention to the utility of cytokeratin 7 (CK7) in differentiating YST from EAC and CCC. A total of 46 ovarian tumors were retrieved for this study: 16 YST, 19 EAC, and 11 CCC. The three groups were analyzed for the expression of CK7, AFP, Leu-M1 (CD15), EMA, and WT1 by immunohistochemistry. In addition, CK and c-kit (CD117) were studied in the YSTs. All of the YSTs tested (100%) were positive for CK. CK7 was considered negative in all 16 YST cases (100%), although a few tumor cells (1%-2%) stained in 4 cases. In contrast, 17 of 19 EACs and all 11 CCCs had diffuse 3+ to 4+ positivity for CK7; the two other EACs showed 2+ positivity for CK7 (40% and 30% of the tumors). AFP was positive in 12 of 15 YSTs (80%), but was generally focal with 1+ staining in 10 cases (67%); only 2 cases were 3+. All of the EACs and CCCs were negative for AFP. Leu-M1 was 1+ in 9 of 15 YSTs (60%), while the remaining 6 were considered negative. Leu-M1 was positive in 10 of 15 EACs tested (67%), but the staining was variable with 1 case 3+, 3 cases 2+, and 6 cases 1+. In the CCCs, 10 cases (91%) were 3+ to 4+, and 1 case was 1+. EMA was essentially negative in 15 of 15 YSTs (100%), with 3 completely negative and 12 showing very focal (<5%) staining. Eight of 12 EACs showed 4+ staining, 3 showed 3+ staining, and 1 showed 2+ staining. All of the 11 CCCs (100%) showed 4+ staining. WT1 was negative in all cases of YST and CCC; 16 of 18 EAC tested (89%) were negative for WT1, but 2 (11%) were 4+ positive. C-kit was negative in all YSTs. In conclusion, it is important for pathologists to be aware that YSTs may mimic EACs and CCCs and that this distinction is important for the clinical management of patients with these tumors. AFP staining is focal in most YST, so an absence of staining does not exclude this diagnosis. CK7 and EMA are essentially negative in YST but are diffusely positive in CCC and EAC, making them useful markers for differentiating YSTs from both CCCs and EACs. Leu-M1 may also be helpful for distinguishing YSTs from CCCs.

Topics: Adenocarcinoma, Clear Cell; alpha-Fetoproteins; Biomarkers, Tumor; Carcinoma, Endometrioid; Diagnosis, Differential; Endodermal Sinus Tumor; Female; Humans; Immunohistochemistry; Keratin-7; Keratins; Lewis X Antigen; Mucin-1; Ovarian Neoplasms; Proto-Oncogene Proteins c-kit; WT1 Proteins

Cells of the human tumor cell line RMG-1, derived from a clear-cell adenocarcinoma of the ovary, were injected intraperitoneally into nude mice, and the cells obtained from the tumor nodules in the mesenterium were found to form a larger number of, and larger-sized, tumor nodules than the original RMG-1 cells. The RMG-1-h cells, transferred into culture from the tumor nodules after a 4th in vivo passage, showed a dissemination potential as high as that of cells disseminating directly from the tissues, and exceedingly higher than that of RMG-1 cells. To assess the molecular bases of the different biological properties of RMG-1 and RMG-1-h cells, we compared the content and expression of various carbohydrate antigens in both cells. The chromosomal profile of RMG-1-h cells revealed their human origin and was identical to that of the original RMG-1 cells. In contrast to the broad histogram for the Le(x)-bearing cells among RMG-1 cells in flow cytometry, the weakly and moderately positive cells toward anti-Le(x) antibody were found to be eliminated from the histogram for the RMG-1-h cells, resulting in the enrichment of cells strongly expressing Le(x), which may account for the high dissemination potential. In addition, the adhesion of RMG-1 cells to mesothelial cells was found to be significantly inhibited by pretreatment of the cells with anti-Le(x) antibody, indicating Le(x)-mediated cell-to-cell interaction between ovarian cancer cells and mesothelial cells. By TLC-immunostaining, two Le(x)-glycolipids, III3Fuc alpha-nLc4Cer and V3Fuc alpha-nLc6Cer were detected in both RMG-1 and RMG-1-h cells, and their total concentrations were not significantly different from each other. However, the hydrophobic moieties of Le(x)-glycolipids in RMG-1-h cells were different from those in RMG-1 cells, suggesting that a difference in the structure of the hydrophobic moieties of Le(x) is partly involved in the enhanced reactivity of RMG-1-h cells toward anti-Le(x) antibody. Thus, the high dissemination potential of ovarian cancer cells was shown to be mediated by the Le(x)-determinant and the Le(x)-bearing cells are enriched by repeated in vivo passage of the cells into nude mice.

Topics: Adenocarcinoma, Clear Cell; Animals; Cell Adhesion; Cell Separation; Chromatography, Thin Layer; Epithelium; Female; Flow Cytometry; Glycolipids; Humans; Karyotyping; Lewis X Antigen; Mice; Mice, Nude; Neoplasm Metastasis; Neoplasm Transplantation; Ovarian Neoplasms; Spectrometry, Mass, Fast Atom Bombardment; Tumor Cells, Cultured

There are similarities between clear cell epithelial ovarian carcinoma and endodermal sinus tumours. Apart from the morphological and clinical characteristics there are immunohistochemical markers of value in differentiating these 2 tumours and the detection of a raised serum AFP is characteristic of endodermal sinus tumours. These 3 cases we describe show the fallibility of the classical differentiating criteria between these two tumours.

Topics: Adenocarcinoma, Clear Cell; Adult; alpha-Fetoproteins; CA-125 Antigen; Diagnosis, Differential; Endodermal Sinus Tumor; Female; Humans; Immunohistochemistry; Lewis X Antigen; Middle Aged; Ovarian Neoplasms