Expression of Friend Leukemia Integration-1 (Fli-1) and the Apoptosis Regulator B Cell Lymphoma-2 (BCL-2) in Gastric Carcinoma; an Immunohistochemical Study

Fibroblast activation protein (FAP) expression in CK5/6 expressed (Basal subtype) & CK20 expressed (Luminal subtype) urothelial bladder carcinoma: an immunohistochemical study

Urinary bladder cancer incidence varies all over the world. Egypt displays high incidence rates. Molecular subtyping helps risk stratification and personalized treatment. Cancer-associated fibroblasts (CAFs) in the tumor microenvironment may provoke tumor-promotion or tumor suppression. Fibroblast activation protein (FAP) is a marker of CAFs, suggested to accelerate tumor progression in various cancers. In urothelial carcinoma, investigations regarding impact of FAP expression on prognosis are needed. This work aims to study impact of FAP expression in urothelial carcinoma and find its relation to CK 5/6 (basal) expressed and CK 20 (luminal) expressed immunohistochemical markers. This retrospective study included 70 urothelial carcinoma specimens. Immunohistochemistry was performed and results were analyzed. FAP was expressed in 67.1% of cases and showed significant association with advanced tumor stage, muscle invasion, mitoses in tumor cells and stratified groups; as 73.9% of FAP positive cases were of Ck5/6+/Ck20- (basal subtype). All studied parameters did not show significant association with patient's overall survival. In conclusion, FAP could have a role in modulating tumor microenvironment and promoting tumor invasion. FAP is correlated with basal subtype of urothelial carcinoma, which may be an indicator of tumor aggressiveness. FAP antagonists may be helpful in preventing tumor progression.

Transcription factor Fli-1 as a new target for antitumor drug development

The transcription factor Friend leukemia virus integration 1 (Fli-1) belonging to the E26 Transformation-Specific (ETS) transcription factor family is not only expressed in normal cells such as hematopoietic stem cells and vascular endothelial cells, but also abnormally expressed in various malignant tumors including Ewing sarcoma, Merkel cell sarcoma, small cell lung carcinoma, benign or malignant hemangioma, squamous cell carcinoma, adenocarcinoma, bladder cancer, leukemia, and lymphoma. Fli-1 binds to the promoter or enhancer of the target genes and participates in a variety of physiological and pathological processes of tumor cells, including cell growth, proliferation, differentiation, and apoptosis. The expression of Fli-1 gene is related to the specific biological functions and characteristics of the tissue in which it is located. In tumor research, Fli-1 gene is used as a specific marker for the occurrence, metastasis, efficacy, and prognosis of tumors, thus, a potential new target for tumor diagnosis and treatment. These studies indicated that Fli-1 may be a specific candidate for antitumor drug development. Recent studies identified small molecules regulating Fli-1 thanks to our screened strategy of natural products and their derivatives. Therefore, in this review, the advanced research on Fli-1 as a target for antitumor drug development is analyzed in different cancers. The inhibitors and agonists of Fli-1 that regulate its expression are introduced and their clinical applications in the treatment of cancer, thus providing new therapeutic strategies.