Table 1.
The summary of cases.
Table 2.
Antibody and staining conditions.
Fig 1.
Distribution of FOXL2-positive stromal cells in the ovary.
(A and B) Normal ovarian cortex. Almost all stromal cells as well as granulosa cells (arrow head) show nuclear positivity for FOXL2. By contrast, none of the cells that constitute blood vessels (asterisk) have nuclear FOXL2. (C and D) Primary mucinous carcinoma. (E and F) Primary serous carcinoma. (G and H) Secondary ovarian tumor (ovarian metastasis of rectal adenocarcinoma). Most stromal spindle cells show nuclear positivity for FOXL2. (I and J) Primary endometrioid carcinoma, a rare example of primary ovarian cancer containing only a few FOXL2-postive cells. H&E (left panels) and FOLX2 immunostaining of the corresponding area (right panels; only nuclear staining is considered positive). Arrows indicate FOXL2-positive cells. The bar in (A) indicates 50μm, and the magnification is identical for all the pictures.
Fig 2.
Distribution of FOXL2-positive stromal cells in extraovarian lesions.
(A and B) A metastatic site of mucinous ovarian carcinoma in the lung (the same case as Fig 1C and 1D). There are no FOXL2-positive stromal cells. (C and D) A peritoneal seeding site of serous ovarian carcinoma (the same case as Fig 1E and 1F). There are few FOXL2-positive cells. (E and F) The primary site of rectal cancer that caused secondary ovarian tumor (the same case with Fig 1G and 1H). There are no FOXL2-positive stromal cells. H&E (left panels) and FOLX2 immunostaining of the corresponding area (right panels). Arrows indicate FOXL2-positive cells. The bar in (A) indicates 50μm, and the magnification is identical for all the pictures.
Fig 3.
The proportion of FOXL2-positive cells in cancer stroma.
The proportion of FOXL2-positive cells on each tissue section was scored using 5-tired scale and the results were plotted. High percentages of cancer stromal cells were FOXL2-positive in the ovary, whereas there were almost no FOXL2-positive cells outside the ovary (Ext-O). Asterisks indicate a significant difference between the groups by Mann-Whitney test (p < 0.05).
Fig 4.
Expression of ASMA and FAP by FOXL2-positive ovarian cells.
(A-C) Tumor tissues were double stained for FOXL2 and ASMA or FAP. Nuclear FOXL2 was stained brown whereas cytoplasmic ASMA and FAP were stained red in B and C, respectively. Some FOXL2-positive cells were also stained positive for ASMA or FAP (arrows), but others were negative (arrow heads). (D and E) The frequency of ASMA and FAP positive cells in FOXL2-positive cells. ASMA and FAP were variously but at least focally expressed by FOXL2-positive cells of all cases. Asterisks indicate a significant difference between two groups (Kruskal-Wallis test followed by multiple comparison).
Fig 5.
Correlation between chronic inflammation and FOXL2-positive cells in ovarian cancer stroma.
(A-E) An example of endometrioid carcinoma where FOXL2-positive stromal cells were scant (FOXL2-poor). (A) Low magnification of H&E. The area above the dotted line is cancer tissue and the area below the line is a pre-existing endometrial cyst. (B and C) CD138 immunostaining. Tumor area (B: red square in A) contained no plasma cells and nontumor area (C: blue square in A) had a few plasma cells (arrows). (D and E) CD163 immunostaining. Both tumor area (D) and nontumor area (E) had some macrophages (arrows). (F-I) The number of CD138-positive plasma cells (F and G) or CD163-positive macrophages (H and I) in one high power field was plotted, comparing between cases with FOXL2-poor stroma (score1 and 2) and those with FOXL2-rich stroma (score 3 and 4). The presence of plasma cells apart from tumor cells correlated with FOXL2-positive cell population, whereas the presence of plasma cells near tumor cells or macrophages in any place did not. The asterisk indicates a significant difference between the groups by Mann-Whitney test (p < 0.05).