title: Synovial sarcoma: immunohistochemical expression of P-glycoprotein and glutathione S transferase-pi and clinical drug resistance.
abstract: Our purpose was to study the role of the expression of P-glycoprotein (Pgp) and glutathione S transferase-pi (GST-pi) in predicting the response to chemotherapy, relapse-free interval, and survival of patients with synovial sarcoma (SS). Thirty-seven cases of primary SS, without regional lymph node or distant metastases, were studied. There were 17 females and 20 males, ranging in age from 7 to 81 years (median, 31 years) with tumors located in the lower extremity (n = 24) upper extremity (n = 5) and trunchus (n = 8). The cases were retrospectively studied without knowledge of clinical course to compare the immunohistochemical expression of Pgp and GST-pi, flow cytometry parameters (ploidy and % of cells in S+G2 phases), and PCNA and Ki-67 labeling of primary tumors before any therapy, with that observed in local recurrences and metastases after chemotherapy. The relationship of the aforementioned parameters with clinicopathological features (gender, age, and histo-blood group of the patients, size, location, histological subtype. TNM stage, and clinical response to chemotherapy of the tumors) was also evaluated. Results revealed that Pgp and GST-pi were expressed in 29.7% and 40.5% of the cases, respectively. In 48.6% of the tumors there was expression of a least one of the drug resistance markers. The markers were coexpressed in 25.0% of the tumors. The prevalence of Pgp expression was lower, but not significantly, in stage I-II (17.6%) than in stage III (40.0%) tumors, and also in cases without clinical progression (16.7%), than in cases with (36.0%). No such differences were observed for GST-pi expression. Pgp and GST-pi expressions were significantly associated with biphasic SS and were particularly noticeable in solid/glandular areas of biphasic SS. The expression of the drug resistance markers was not significantly associated with gender, age, and histo-blood group of the patients, dimension, location, and proliferative activity of the tumors; it was also not significantly related to relapse-free interval and survival of the patients. The expression of Pgp and GST-pi was not significantly associated either to response to chemotherapy or influenced by chemotherapy. We conclude that Pgp and GST-pi expressions are not good predictors response to of the chemotherapy in patients with localized SS. Other drug resistance mechanisms may be active in SS.
authors.affiliation: Unit of Molecular Pathology-IPATIMUP, Medical Faculty, Portugal.
authors.forename: J M
authors.initials: JM
authors.lastname: Lopes
authors.forename: O S
authors.initials: OS
authors.lastname: Bruland
authors.forename: B
authors.initials: B
authors.lastname: Bjerkehagen
authors.forename: M C
authors.initials: MC
authors.lastname: Silva
authors.forename: R
authors.initials: R
authors.lastname: Holm
authors.forename: E O
authors.initials: EO
authors.lastname: Pettersen
authors.forename: O P
authors.initials: OP
authors.lastname: Solheim
authors.forename: M
authors.initials: M
authors.lastname: Sobrinho-Simões
authors.forename: J M
authors.initials: JM
authors.lastname: Nesland
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000096:biosynthesis; D002648:Child; D004273:DNA, Neoplasm / Q000032:analysis; D019008:Drug Resistance, Neoplasm; D005260:Female; D005434:Flow Cytometry; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000096:biosynthesis*; D007592:Joint Diseases / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013584:Sarcoma, Synovial / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D015996:Survival Rate
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D007527:Isoenzymes; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase