Breast Cancer Res Treat (2008) 107:249–257 255 Signiﬁcance BCSS 95% CI for HR HR 0.804 0.777 1.439 1.884 1.931 1.390 2.380 0.567 0.689 0.677 0.846 0.793 1.463 1.439 2.258 1.658 2.410 1.158 1.090 1.394 Lower 0.653 0.631 1.129 1.547 1.330 1.139 1.965 0.420 0.513 0.489 0.683 0 .644 1.152 1.181 1.618 1.346 1.984 0.803 0.765 0.973 Table 4 Cox proportional hazard regression analysis showing hazard ratios and P- values in patients with invasive breast carcinoma * Grade 1—well differentiated Grade 2—moderately differentiated Grade 3—poorly differentiated HR = adjusted hazard ratio, CI = conﬁdence interval and BCSS = Breast Cancer Speciﬁc Survival (a) Training set Mast cells ER Her2 Size of the lesion 2–5 cm vs. £2 cm >5 cm vs. £2 cm Grade* Grade 1, 2 vs. Grade 3 Nodal status Age 40–49 vs. <40 50–65 vs. <40 >65 vs. <40 (b) Validation set Mast cells ER Her2 Size of the lesion 2–5 cm vs. £2 cm >5 cm vs. £2 cm Grade* Grade 1, 2 vs. Grade 3 Nodal status Age 40–49 vs. <40 50–65 vs. <40 >65 vs. <40 0.041 0.018 0.003 0.000 0.001 0.001 0.000 0.000 0.013 0.019 0.128 0.0289 0.0018 3.07 · 10–4 1.66 · 10–6 1.96 · 10–6 7.06 · 10–19 0.432 0.634 0.07 inhibits angiogenesis by exerting cytotoxic effect on vascular smooth muscles [34]. MC tryptase stimulates inﬂammation and recruits ﬁbroblasts leading to tumor ﬁbrosis, and thereby limiting tumor growth and metastasis [35]. Tryptase, however, is also implicated in angiogene- sis and its effect correlated with a better response to chemotherapy in ovarian cancer. This suggests that MC tryptase-mediated ﬁbrosis and angiogenesis may be responsible for the good prognostic effect seen in advanced ovarian cancer [13]. In this TMA study, we showed that the presence of even one or more MCs in the tumor microenvironment was sufﬁcient to exert a positive prognostic effect. Our ﬁnding supports the idea of assessing inﬂammatory cell inﬁltrates as prognostic markers in cancer. In our previously pub- lished pilot report, we had observed no correlation between the presence of stromal MCs with either B-cells (CD20- positive) or T-cells (CD3-positive) [11], and hence we did not stain for these inﬂammatory cells in this study. We also did not ﬁnd a statistically signiﬁcant prognostic effect of MCs in the node-negative groups in the training set anal- ysis. This differs from our earlier published report [11] on a 348 case series which concluded that the presence of MCs was a favourable prognostic factor in the node-negative patients (P = 0.018) but not the node-positive group (P = 0.384). This ﬁnding underscores the importance of validating clinically relevant ﬁndings on a larger series of patients and using the test-validation approach to arrive at a meaningful conclusion. A number of studies have elaborated on the role of immune cells in cancer etiopathogenesis. T regulatory (Treg) cells are known to be associated with poor outcome in ovarian cancer [36] and the initial results of a clinical trial aimed at speciﬁcally eliminating Treg cells has shown promising results [37]. Lymphoma-associated macrophag- es have been used to predict the outcome of follicular lymphoma [38] and reactive macrophages are used to predict breast, prostate, ovarian, and cervical cancer Upper 0.991 0.957 1.834 2.295 2.803 1.696 2.882 0.765 0.924 0.938 1.049 0 .976 1.859 1.753 3.151 2.042 2.927 1.671 1.552 1.998 123