Increased proliferation activity measured by immunoreactive Ki67 is associated with survival improvement in rectal/recto sigmoid cancer.
OBJECTIVE
To assess the expression of Ki67 as prognosticator in rectal/recto sigmoid cancer.


METHODS
Samples from 146 patients with rectal and recto sigmoid cancer were studied for expression of Ki67 and its prognostic significance in comparison with clinico-pathological predictors of survival. Formalin-fixed, paraffin-embedded tissues from 6 (4.1%) patients with T1, 26 (17.8%) with T2, 94 (64.4%) with T3, and 20 (13.7%) with T4 tumors were studied. Ki67 expression was determined immunohistochemically. Samples were divided according to mean value into high (>40%) and low (< or =40%) expression. Areas of extensive proliferation (>50%) were defined as "hot spot" areas.


RESULTS
Hot spot areas were present in samples regardless of histopathological grade. Lower TNM and Dukes stage and higher expression of Ki67 and presence of Ki67 hot spot areas in histopathological samples were associated with better survival, whereas no association was observed with histopathological grade (P = 0.78). In Cox multivariate regression analysis, significant prognostic factors were Dukes stage (P<0.001), presence of lymph node metastases (P = 0.015), age (P = 0.035) and presence of Ki67 hot spot areas (P = 0.044).


CONCLUSIONS
Proliferative activity as measured by Ki67 in rectal cancer is associated with survival improvement compared with patients with low Ki67. Areas of prognostically significant increased proliferation were found independently of histopathological tumor grade.
Salminen
Eeva
E
Department of Oncology and Radiotherapy, POB 52, Fin-20510 Turku, Finland. eevsal@utu.fi
Palmu
Salla
S
Vahlberg
Tero
T
Roberts
Peter-J
PJ
Söderström
Karl-Owe
KO
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000276:immunology / Q000378:metabolism; D002455:Cell Division; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012004:Rectal Neoplasms / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology; D012811:Sigmoid Neoplasms / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen