Stromal mast cells in invasive breast cancer are a marker of favourable prognosis: a study of 4,444 cases.
OBJECTIVE
We have previously demonstrated in a pilot study of 348 invasive breast cancers that mast cell (MC) infiltrates within primary breast cancers are associated with a good prognosis. Our aim was to verify this finding in a larger cohort of invasive breast cancer patients and examine the relationship between the presence of MCs and other clinical and pathological features.


METHODS
Clinically annotated tissue microarrays (TMAs) containing 4,444 cases were constructed and stained with c-Kit (CD-117) using standard immunoperoxidase techniques to identify and quantify MCs. For statistical analysis, we applied a split-sample validation technique. Breast cancer specific survival was analyzed by Kaplan-Meier [KM] method and log rank test was used to compare survival curves.


RESULTS
Survival analysis by KM method showed that the presence of stromal MCs was a favourable prognostic factor in the training set (P = 0.001), and the validation set group (P = 0.006). X-tile plot generated to define the optimal number of MCs showed that the presence of any number of stromal MCs predicted good prognosis. Multivariate analysis showed that the MC effect in the training set (Hazard ratio [HR] = 0.804, 95% Confidence interval [CI], 0.653-0.991, P = 0.041) and validation set analysis (HR = 0.846, 95% CI, 0.683-1.049, P = 0.128) was independent of age, tumor grade, tumor size, lymph node, ER and Her2 status.


CONCLUSIONS
This study concludes that stromal MC infiltration in invasive breast cancer is an independent good prognostic marker and reiterates the critical role of local inflammatory responses in breast cancer progression.
Rajput
Ashish B
AB
Department of Pathology, Genetic Pathology Evaluation Centre, University of British Columbia, Vancouver, BC, Canada.
Turbin
Dmitry A
DA
Cheang
Maggie Cu
MC
Voduc
David K
DK
Leung
Sam
S
Gelmon
Karen A
KA
Gilks
C Blake
CB
Huntsman
David G
DG
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D018450:Disease Progression; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008407:Mast Cells / Q000166:cytology / Q000378:metabolism*; D008875:Middle Aged; D010865:Pilot Projects; D011379:Prognosis; D016016:Proportional Hazards Models; D017154:Stromal Cells / Q000166:cytology / Q000378:metabolism*