Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0007095 (carcinoid)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a group of 30 human tumors, comprising 12 lung, 14 ovarian, 2 breast carcinomas, 1 hypernephroma and 1 mid-gut carcinoid, the expression of major histocompatibility complex (MHC) class I molecules and the intercellular adhesion molecule 1 (CAM-1, CD54) was found to vary independently. Some tumors expressed both or neither of these molecules. Among 9/13 ICAM-1+ tumors, in which greater than 50% cells reacted with the anti-ICAM-1 monoclonal antibody (mAb) (LB-2), the class I antigen was also detected on greater than 50% of the cells. Only 2 ICAM-1+ tumors were class-I-. In 5/17 cases the tumors were MHC-class-I+ and ICAM-1-. Lymphocytes collected from the blood or from the tumor site were assayed for recognition on the tumor cells in the auto-tumor cytotoxicity test and in mixed lymphocyte tumor cell culture (MLTC). Positive results were obtained only with the MHC-class-I+/ICAM-1+ tumors. In vitro treatment of the tumor cell suspensions with interferon gamma and tumor necrosis factor alpha (TNF alpha) induced or enhanced the ICAM-1 and/or class I antigen expression in 8/12 cases. Of the tumor samples treatged, 8/9 acquired stimulatory capacity and 3/10 became susceptible to lysis by the lymphocytes. In 6/6 MLTC performed with the cytokine-treated tumor cells, cytotoxicity against the autologous tumor was generated. Three of these MLTC lymphocytes also lysed the untreated targets. mAb directed to class I antigens or to ICAM-1 inhibited both the stimulation by and the lysis of tumor cells when confronted with fresh lymphocytes. The cytotoxicity generated in the MLTC was also inhibited. If, however, the cytotoxic function was induced in MTLC containing interleukin-2 (5 U/ml), inhibition was obtained only by pretreatment of the targets with mAb against ICAM-1. The results show thus (a) that the lymphocytes react in vitro with tumor cells only if these express both MHC class I molecules and ICAM-1; (b) that expression of these molecules can be induced by interferon alpha and TNF alpha; (c) that cytotoxic effectors generated in the MLTC with cytokine-treated tumors can also act on the untreated tumor cells. The requirement of the two surface moieties for the interaction with lymphocytes was also substantiated by blockade with relevant mAb.
 ...
PMID:Expression of the adhesion molecule ICAM-1 and major histocompatibility complex class I antigens on human tumor cells is required for their interaction with autologous lymphocytes in vitro. 196 61

Cryosections of 28 primary and metastatic midgut carcinoid tumors from 12 patients with carcinoid syndrome were investigated immunohistochemically with antibodies that recognize human MHC class I (HLA-ABC) and class II (HLA-DR) antigens. The tumor parenchyma of all six patients treated with interferon alpha (IFN-alpha) during a mean 8.6 months (3 x 10(6) to 5 x 10(6) U three times weekly) exhibited unequivocal HLA-ABC immunoreactivity, with only minor discrepancies between primary lesions and metastases in mesenteric lymph nodes and liver. Class I staining was absent on the tumor cells of all 14 specimens from the patients without IFN therapy but was induced by culturing freshly dispersed tumor cells in vitro for 48 hours in the presence of recombinant IFN-alpha. The stroma of all neoplasms displayed class I and II immunostaining, as did usually a few CD4-expressing cells. The carcinoid specimens lacked parenchymal HLA-DR immunoreactivity, which is interesting considering suggestions on improved prognosis for bowel carcinomas lacking the class II expression. The study supports the idea that induction of MHC class I antigens could contribute to the beneficial clinical effect of IFN-alpha treatment in patients with midgut carcinoid tumors.
 ...
PMID:MHC class I and II antigen expression and interferon alpha treatment of human midgut carcinoid tumors. 772 32

We studied the expression of major histocompatibility complex (MHC) class I molecule in 52 ex-vivo tumor samples comprising 29 ovarian, 15 lung, 1 breast, and 4 colon carcinomas; 1 midgut carcinoid; and 2 malignant mesenchymal tumors obtained from surgical specimens or from malignant effusions. The allelic products were visualized in untreated and interferon gamma + tumor necrosis factor alpha treated aliquots of tumor cells and in the patient's blood lymphocytes by the one-dimensional isoelectric focusing method. Generally, the tumor cells contained lower amounts of MHC class I molecules compared to the lymphocytes. In vitro exposure to interferon gamma and tumor necrosis factor alpha elevated the level of MHC class I expression in 24 of 52 tumors and corrected the assembly defect seen in 2 cases. In 20 tumors one or several human leukocyte antigen alleles were undetectable even after cytokine treatment. Correlation was seen with the grade of differentiation; the proportion of tumors with selective losses in poorly, moderately, or well differentiated tumors were 16 of 30, 3 of 13, and 1 of 9, respectively. Selective losses occurred in ovarian carcinoma cells collected from malignant effusions (12 of 22, 54%) but not in 7 primary tumors. In primary lung carcinomas the frequency was 36% (5 of 14 cases). Thirty-nine patients were serologically typed; thus the MHC alleles on the tumor cells could be identified. In this panel of tumors 30 human leukocyte antigen alleles were represented. Among these the expression of 15 was found to be down-regulated in some but not all tumors of the same histology.
 ...
PMID:Selectively down-regulated expression of major histocompatibility complex class I alleles in human solid tumors. 848 28