Introduction Lymphocyte infiltration (LI) is often seen in breast cancer but its importance remains controversial. A positive correlation of human epidermal growth factor receptor 2 (HER2) amplification and LI has been described, which was associated with a more favorable outcome. However, specific lymphocytes might also promote tumor progression by shifting the cytokine milieu in the tumor.

IntroductionCurrent prognostic gene expression profiles for breast cancer mainly reflect proliferation status and are most useful in ER-positive cancers. Triple negative breast cancers (TNBC) are clinically heterogeneous and prognostic markers and biology-based therapies are needed to better treat this disease.MethodsWe assembled Affymetrix gene expression data for 579 TNBC and performed unsupervised analysis to define metagenes that distinguish molecular subsets within TNBC. We used n = 394 cases for discovery and n = 185 cases for validation. Sixteen metagenes emerged that identified basal-like, apocrine and claudin-low molecular subtypes, or reflected various non-neoplastic cell populations, including immune cells, blood, adipocytes, stroma, angiogenesis and inflammation within the cancer. The expressions of these metagenes were correlated with survival and multivariate analysis was performed, including routine clinical and pathological variables.ResultsSeventy-three percent of TNBC displayed basal-like molecular subtype that correlated with high histological grade and younger age. Survival of basal-like TNBC was not different from non basal-like TNBC. High expression of immune cell metagenes was associated with good and high expression of inflammation and angiogenesis-related metagenes were associated with poor prognosis. A ratio of high B-cell and low IL-8 metagenes identified 32% of TNBC with good prognosis (hazard ratio (HR) 0.37, 95% CI 0.22 to 0.61; P < 0.001) and was the only significant predictor in multivariate analysis including routine clinicopathological variables.ConclusionsWe describe a ratio of high B-cell presence and low IL-8 activity as a powerful new prognostic marker for TNBC. Inhibition of the IL-8 pathway also represents an attractive novel therapeutic target for this disease.

Beside their structural role for the cell membrane the family of sphingolipids act as effector molecules in signal transduction with links to various aspects of cancer initiation, progression and treatment response. The "sphingolipid rheostat" balances between apoptosis inducing ceramid and growth promoting sphingosine-1-phosphate. We analyzed gene expression of 43 proteins from this pathway in different subtypes of breast cancer using microarray data of 1,269 tumor samples (test set n=171; validation sets n=1098) and observed significant differences for several genes. Sphingosine kinase 1 (SPHK1), ceramide galactosyltransferase (UGT8), and Ganglioside GD3-Synthase (ST8SIA1) displayed higher expression among ER negative tumors. In contrast, glucosylceramidsynthase (GCS), dihydroceramidsynthases (LASS4, LASS 6) and acid ceramidase (ASAH1) were higher expressed in ER positive samples. Survival analysis revealed a worse outcome of patients with high SPHK1 expression. To avoid a confounding effect of the ER status we also restricted the analysis to 750 patients with ER positive tumors. Again a worse outcome was observed for tumors displaying high SPHK1 expression. While 75.8+/-1.9% of the patients with tumors low in SPHK1 expression were free of metastasis at 5 years, this was the case for only 64.9+/-3.6% of patients with tumors displaying high SPHK1 expression (P=0.008). Immunohistochemistry identified the carcinoma cells as the major source of SPHK1 expression in the tumor. The correlation of SPHK1 with a poor prognosis as well as its high expression among ER negative tumors are in line with the antiapoptotic and proliferative properties of its product sphingosine-1-phosphate. Targeting of the sphingolipid rheostat may thus open new treatment options.

Our previous data indicate that the expression of the PLK gene which codes for a serine/threonine kinase is restricted to proliferating cells. In Northern blot experiments PLK mRNA expression was at the limit of detection in normal lung tissue but elevated in most samples of non-small cell lung cancer (NSCLC). A very low frequency of PLK transcripts was only found in bronchiolo-alveolar carcinomas. NSCLC patients whose tumors showed moderate PLK expression survived signi®cantly longer (5 year survival rate=51.8%) than those with high levels of PLK transcripts (24.2%, P=0.001). No statistically signi®cant correlation was found between PLK mRNA expression and age, sex, TNM status, histological type or degree of dierentiation. Interestingly, the prognosis of patients in postsurgical stages I and II was correlated with PLK expression (5 year survival rates in stage I: 69.1% (moderate PLK) ± 43.5% (high PLK), P=0.03 or in stage II: 51.9% (moderate PLK) ± 9.9% (high PLK), P=0.006). These results suggest that PLK mRNA expression provides a new independent prognostic indicator for patients with NSCLC.

We have Identified the nucleotide sequence of the cDNA encoding the human counterpart of the moue gene Plk (polo-like kinase). . Activated Ras mediates signal transmission from receptor tyrosine kinases to a cascade of serine/threonine kinases including c-Raf, MEK, MAP kinase, and RSK (9). Many observations suggest that MAP kinase and RSK, which are located in the cytoplasm and in the nucleus, directly influence gene expression by phosphorylation of transcription factors (10, 11). Very recently, a MEK kinase independent ofRaf-1 has been described (12). Still, many components of this mitogenic cascade, such as protein kinases and many of their interactions, remain to be discovered.We and others have cloned cDNAs of novel protein kinases by using degenerate oligonucleotide primers for the PCR amplification of reverse-transcribed mRNA (13)(14)(15)(16)(17). A principal attraction of this approach is that based on conserved motifs of the kinase domain it allows amplification of protein kinases which are expressed at very low frequency. Here, we describe the PCR-based identification of a gene coding for a protein kinase from embryonic tissue. The complete cDNA was subsequently isolated from a cDNA library based on RNA from a squamous-cell lung carcinoma. The cDNA encodes a protein which seems to be the human counterpart of a mouse protein referred to as Plk (polo-like kinase) and contains structural hallmarks of protein-serine/ threonine kinases.t We show that expression of human PLK mRNA is increased in proliferating tissues like human tumors, as well as in cell lines and growth-stimulated primary cells. In quiescent cells, PLK transcripts were not found. These data suggest that PLK mRNA expression is tightly linked to proliferation.