We previously reported a strong IL4I1 gene expression in primary mediastinal B-cell lymphoma (PMBL) and recently identified the protein as a secreted L-phenylalanine oxidase, physiologically ...expressed by myeloid cells, which inhibits T-cell proliferation in vitro. Here, we analyzed the pattern of IL4I1 protein expression in 315 human lymphoid and non-lymphoid malignancies. Besides PMBL, IL4I1 expression in tumors was very frequent. IL4I1 was detected in tumor-associated macrophages from most of the tumors and in neoplastic cells from follicular lymphoma, classic and nodular lymphocyte predominant Hodgkin lymphomas and small lymphocytic lymphoma, three of which are germinal center derived. IL4I1-positive tumor cells were also detected in rare cases of solid cancers, mainly mesothelioma. The enzymatic activity paralleled protein expression, suggesting that IL4I1 is functional in vivo. Depending on the tumor type, IL4I1 may impact on different infiltrating lymphocyte populations with consequences on tumor evolution. In the particular case of follicular lymphoma cells, which are susceptible to antitumor cytotoxic T cells killing but depend on interactions with local T helper cells for survival, a high level of IL4I1 expression seems associated with the absence of bone marrow involvement and a better outcome. These findings plead for an evaluation of IL4I1 as a prognosis factor.
Post-radiation atypical vascular lesions of the skin display clinical and morphological overlap with well-differentiated angiosarcomas, and correct diagnosis may be difficult.
We studied clinical, ...histological and immuno-histochemical aspects (CD31, CD34, D2-40 and VEGFR-3) of eight post-radiation atypical vascular lesions comparatively with three post-radiation angiosarcomas.
All patients were female and received radiation therapy for breast carcinoma. On average, atypical vascular lesions occurred 4.3 years after radiation therapy and presented as small papulonodules or erythematous plaques. The clinical course after simple excision was benign. Histologically, they were relatively circumscribed lesions and showed slit-like vessels dissecting dermal collagen in all cases. On average, angiosarcomas occurred 5 years after radiation therapy and presented as more extensive lesions with a more aggressive clinical course. The lesions showed histological overlap with atypical vascular lesions, but were poorly circumscribed, with deeper invasion, cytological atypia and mitosis. Although the immuno-histochemical profiles were similar, expression of VEGFR-3 was greater in two cases of angiosarcoma.
Post-radiation atypical vascular lesions are benign lesions that display clinical, histological and immuno-phenotypic overlap with well-differentiated angiosarcoma, and diagnosis requires good clinicopathological correlation. VEGFR-3 may be useful for differential diagnosis, as well as amplification of the MYC gene.
Summary We investigated the expression of SOX9, a transcription factor linked to the hedgehog pathways, and desert hedgehog, previously shown to be expressed in a malignant peripheral nerve sheath ...tumor cell line, in neurofibromatosis 1 tumors (neurofibromas and malignant peripheral nerve sheath tumor), and in a group of sporadic spindle cell sarcomas. We found that SOX9 was expressed in Schwann cells from neurofibromatosis 1 tumors, and was significantly up-regulated in malignant peripheral nerve sheath tumor versus neurofibromas at the protein level ( P < .0001) and in malignant peripheral nerve sheath tumor and plexiform neurofibroma as compared to diffuse tumors at the mRNA level ( P = .002 and P = .009, respectively). SOX9, however, was not a specific feature of malignant peripheral nerve sheath tumor because a significant proportion of spindle cell sarcomas unrelated to neurofibromatosis 1 were also positive. Interestingly, within neurofibromas, SOX9 expression correlated to the histology mostly found in plexiform areas, whereas it was negative or weak in diffuse neurofibroma ( P < .0001). In sporadic sarcomas, the proportion of positive cells was actually heterogeneous among cases. Desert hedgehog expression was mostly found in sarcomas ( P = .0002), but diffuse staining was only seen in non–neurofibromatosis 1 tumors, whereas malignant peripheral nerve sheath tumor displayed only focal expression. Finally, we found no significant correlation between the expression of SOX9 and desert hedgehog, and neither SOX9 nor desert hedgehog expression was correlated to the histoprognostic grade in sarcomas. Altogether, these results indicate that, although not a specific feature of neurofibromatosis 1 tumors, SOX9 may play a role in the development of malignant peripheral nerve sheath tumor in patients with neurofibromatosis 1 and does not appear to be linked to autocrine stimulation by the desert hedgehog signaling pathway.
We previously reported a strong IL4I1 gene expression in primary mediastinal B-cell lymphoma (PMBL) and recently identified the protein as a secreted L-phenylalanine oxidase, physiologically ...expressed by myeloid cells, which inhibits T-cell proliferation in vitro. Here, we analyzed the pattern of IL4I1 protein expression in 315 human lymphoid and non-lymphoid malignancies. Besides PMBL, IL4I1 expression in tumors was very frequent. IL4I1 was detected in tumor-associated macrophages from most of the tumors and in neoplastic cells from follicular lymphoma, classic and nodular lymphocyte predominant Hodgkin lymphomas and small lymphocytic lymphoma, three of which are germinal center derived. IL4I1-positive tumor cells were also detected in rare cases of solid cancers, mainly mesothelioma. The enzymatic activity paralleled protein expression, suggesting that IL4I1 is functional in vivo. Depending on the tumor type, IL4I1 may impact on different infiltrating lymphocyte populations with consequences on tumor evolution. In the particular case of follicular lymphoma cells, which are susceptible to antitumor cytotoxic T cells killing but depend on interactions with local T helper cells for survival, a high level of IL4I1 expression seems associated with the absence of bone marrow involvement and a better outcome. These findings plead for an evaluation of IL4I1 as a prognosis factor.
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