PTK7 as a potential prognostic and predictive marker of response to adjuvant chemotherapy in breast cancer patients, and resistance to anthracycline drugs.

Biomarkers predicting resistance to particular chemotherapy regimens could play a key role in optimally individualized treatment concepts. PTK7 (protein tyrosine kinase 7) belongs to the receptor tyrosine kinase family involved in several physiological, but also malignant, cell behaviors. Recent studies in acute myeloid leukemia have associated PTK7 expression with resistance to anthracycline therapy. PTK7 mRNA expression in primary tumor tissue (PTT) and corresponding lymph node tissue (LNT) were retrospectively measured in 117 patients with early breast cancer; PTK7 expression was available in 103 PTT and 108 LNT samples. Median age was 60 years (range, 27-87 years). At a median follow-up of 28.5 months, 6 deaths and 16 recurrences had occurred. PTK7 expression correlations with clinicopathological features were computed and PTK7 expression effects on patient outcome were analyzed in three cohorts defined by adjuvant treatment: anthracycline-based treatment, other chemotherapy regimens (including taxane or other substances), or no chemotherapy. Association of PTK7 expression with clinicopathological features was seen only for age in PTT and nodal stage in LNT. High LN PTK7 was associated with poorer disease-free survival (DFS) in the total population (3-year DFS: low [81.7%] versus high [70.4%]; P=0.016) and in patients without adjuvant chemotherapy (3-year DFS: low [91.7%] versus high [22.3%]; P<0.001), but not in patients receiving adjuvant chemotherapy (P=0.552). DFS stratified by PTK7 expression was compared in treatment cohorts: In patients with low LN PTK7 expression, neither chemotherapy cohort showed significantly better survival than the no-chemotherapy cohort. In patients with high LN PTK7 expression, those receiving chemotherapy, including substances other than anthracyclines, but not those receiving only anthracycline-based chemotherapy, showed significantly better DFS than those receiving no chemotherapy (P=0.001). Our results support earlier findings that PTK7 may be a prognostic and predictive marker associated with resistance to anthracycline-based chemotherapy. Further investigations are needed to validate these findings in breast cancer.

PTK 7 is a transforming gene and prognostic marker for breast cancer and nodal metastasis involvement.

Protein Tyrosin Kinase 7 (PTK7) is upregulated in several human cancers; however, its clinical implication in breast cancer (BC) and lymph node (LN) is still unclear. In order to investigate the function of PTK7 in mediating BC cell motility and invasivity, PTK7 expression in BC cell lines was determined. PTK7 signaling in highly invasive breast cancer cells was inhibited by a dominant-negative PTK7 mutant, an antibody against the extracellular domain of PTK7, and siRNA knockdown of PTK7. This resulted in decreased motility and invasivity of BC cells. We further examined PTK7 expression in BC and LN tissue of 128 BC patients by RT-PCR and its correlation with BC related genes like HER2, HER3, PAI1, MMP1, K19, and CD44. Expression profiling in BC cell lines and primary tumors showed association of PTK7 with ER/PR/HER2-negative (TNBC-triple negative BC) cancer. Oncomine data analysis confirmed this observation and classified PTK7 in a cluster with genes associated with agressive behavior of primary BC. Furthermore PTK7 expression was significantly different with respect to tumor size (ANOVA, p = 0.033) in BC and nodal involvement (ANOVA, p = 0.007) in LN. PTK7 expression in metastatic LN was related to shorter DFS (Cox Regression, p = 0.041). Our observations confirmed the transforming potential of PTK7, as well as its involvement in motility and invasivity of BC cells. PTK7 is highly expressed in TNBC cell lines. It represents a novel prognostic marker for BC patients and has potential therapeutic significance.

PTK7 expression in triple-negative breast cancer.

BACKGROUND: Protein tyrosine kinase-7 (PTK7) plays an important role in cancer. Our aim was to evaluate PTK7 in triple-negative breast cancer (TNBC). MATERIALS AND METHODS: PTK7 Expression was assessed by immunohistochemistry (IHC) in 133 patients with TNBC. Expression levels were correlated with clinicopathological features and survival, taking chemotherapy into account. RESULTS: Positive PTK7 expression was detected in 28.6% of tumors. In the total population, no significant difference was detected in disease-free survival (DFS) or overall survival (OS) related to PTK7 status. However, in patients treated by chemotherapy, patients with PTK7-negative tumors seemed to have better DFS than those with PTK7-positive tumors, particularly for patients treated with only anthracycline-therapy drugs. In patients receiving other chemotherapy regimens, PTK7 status had no significant impact on DFS or OS. CONCLUSION: Our results support earlier findings that PTK7 may be associated with resistance to anthracycline-based chemotherapy.

HER2/neu, Topoisomerase 2a, Estrogen and Progesterone Receptors: Discordance between Primary Breast Cancer and Metastatic Axillary Lymph Node in Expression and Amplification Characteristics.

Molecular classification of breast cancer (BC) and the evaluation of new biological markers such as estrogen receptor (ER), progesterone receptor (PR), ErbB2 (HER2) and topoisomerase 2a (Topo2a) status are claimed to be important parameters in the management of BC therapy. In case of heterogeneity between primary BC and metastatic site, this implies profound limitations of efficient systemic therapy. Therefore, it is essential to analyze whether biological markers of BC relate to identical expression profiles of metastatic lymph nodes (mLNs). We used paraffin-embedded tumor tissue from 119 patients with at least 1 mLN. Immunohistochemistry (IHC) was used to analyze ER, PR, HER2 and Topo2a. In addition, HER2 and Topo2a amplification was evaluated by fluorescence/chromogenic in situ hybridization (FISH/CISH) in all samples with a HER2 score of 2+/3+ by IHC. Overall, the percentage of discordant marker status in the BC and its mLN was 2.6% for ER, 3.5% for PR, 3.4% for HER2, and 3.4% for Topo2a. With FISH/CISH, the amplification rate for Topo2a and HER2 was concordant in all cases. Because there are no prospective studies, it remains unclear whether these discrepancies have an effect on patient survival.