title: [Frequency of association of rheumatoid factor in patients with breast cancer].
abstract: OBJECTIVE
  It has been reported that some patients with cancer present auto-immune phenomenon mediated by auto-antibodies, suggesting a relationship between auto-immunity and cancer. Our interest was to determine the frequency of association of rheumatoid factor and breast cancer.
  
  
  METHODS
  Fifty patients were studied, 3 on stage 111 and 19 on stage IV. Rheumatoid factor was measured in all of them. Auto-antibodies were measured by ELISA. The clinical files of all the patients were reviewed to determine the presence of metastases (osseous, pulmonary, CNS and hepatic) as well as the histological type of the cancer to correlate the expression of the rheumatoid factor with the patients' clinical status.
  
  
  RESULTS
  Four (12.9%) out of the 31 patients on stage 111 had positive rheumatoid factor, while 9 (47.3%) out of 19 patients on stage IV had positive rheumatoid factor. The mean age of the patients on stage 111 with positive rheumatoid factor was 48 years, while the mean age of the patients on stage IV with positive rheumatoid factor was 53 years. Patients on stage 111 with positive rheumatoid factor only had local-regional metastases while patients on stage IV with positive rheumatoid factor had distant metastases. The predominant histological type was adenocarcinoma.
  
  
  CONCLUSIONS
  In this study it is shown that breast cancer on the most advanced stages have higher expression of rheumatoid factor, and more clinical derangement with higher levels of rheumatoid factor expression. The proposal of auto-antibodies as predictors of the severity of the cancer requires further studies on several types of cancer.
authors.affiliation: División de Investigación Clínica, Hospital de Oncología, Centro Médico Nacional Siglo XXI, IMSS.
authors.forename: L G
authors.initials: LG
authors.lastname: del Rivero Hernández
authors.forename: A
authors.initials: A
authors.lastname: Silva Juan
authors.forename: S
authors.initials: S
authors.lastname: Martínez Cairo-Cueto
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000097:blood*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D012217:Rheumatoid Factor / Q000097:blood*
chemical_list: D012217:Rheumatoid Factor