Kinase inhibitors (KIs) represent a growing class of drugs directed at various protein kinases and used in the treatment of both solid tumors and hematologic malignancies. It is a heterogeneous group of compounds that are widely applied not only in different types of tumors but also in tumors that are positive for a specific predictive factor. This review summarizes common cardiotoxic effects of KIs, including hypertension, arrhythmias with bradycardia and QTc prolongation, and cardiomyopathy that can lead to heart failure, as well as less common effects such as fluid retention, ischemic heart disease, and elevated risk of thromboembolic events. The guidelines for cardiac monitoring and management of the most common cardiotoxic effects of protein KIs are discussed. Potential signaling pathways affected by KIs and likely contributing to cardiac damage are also described. Finally, the need for further research into the molecular mechanisms underlying the cardiovascular toxicity of these drugs is indicated.

Intra-tumor heterogeneity (ITH) results from the coexistence of genetically distinct cancer cell (sub)populations, their phenotypic plasticity, and the presence of heterotypic components of the tumor microenvironment (TME). Here we addressed the potential association between phenotypic ITH revealed by mass spectrometry imaging (MSI) and the prognosis of breast cancer. Tissue specimens resected from 59 patients treated radically due to the locally advanced HER2-positive invasive ductal carcinoma were included in the study. After the on-tissue trypsin digestion of cellular proteins, peptide maps of all cancer regions (about 380,000 spectra in total) were segmented by an unsupervised approach to reveal their intrinsic heterogeneity. A high degree of similarity between spectra was observed, which indicated the relative homogeneity of cancer regions. However, when the number and diversity of the detected clusters of spectra were analyzed, differences between patient groups were observed. It is noteworthy that a higher degree of heterogeneity was found in tumors from patients who remained disease-free during a 5-year follow-up (n = 38) compared to tumors from patients with progressive disease (distant metastases detected during the follow-up, n = 21). Interestingly, such differences were not observed between patients with a different status of regional lymph nodes, cancer grade, or expression of estrogen receptor at the time of the primary treatment. Subsequently, spectral components with different abundance in cancer regions were detected in patients with different outcomes, and their hypothetical identity was established by assignment to measured masses of tryptic peptides identified in corresponding tissue lysates. Such differentiating components were associated with proteins involved in immune regulation and hemostasis. Further, a positive correlation between the level of tumor-infiltrating lymphocytes and heterogeneity revealed by MSI was observed. We postulate that a higher heterogeneity of tumors with a better prognosis could reflect the presence of heterotypic components including infiltrating immune cells, that facilitated the response to treatment.

Resistance to trastuzumab in patients with HER2-overexpressing breast cancer is associated with higher risk of progression or cancer death, and might be related to activation of PI3K/AKT/mTOR and Ras/Raf/MAPK signaling cascades and a decreased level of their inhibitor (PTEN). HER2-overexpressing breast cancer patients (n = 75) treated with radical local therapy and trastuzumab in adjuvant setting were included into the study. Deoxyribonucleic acid isolated from paraffin sections was used to assess mutational status of the PIK3CA gene (p.H1047R and p.E545K mutations) by the quantitative polymerase chain reaction technique. Expression of selected proteins (ER, PgR, AR, Ki-67, EGFR) was assessed using immunohistochemistry. In the studied group we found significantly higher Ki-67LI in EGFR-positive carcinomas (p = 0.048). Moreover, EGFR immunonegativity was observed more frequently in low-grade (G1/G2) carcinomas as well as in estrogen/progesterone and androgen receptor immunopositive tumors (p = 0.042, p = 0.016, p = 0.044, respectively). Favorable metastasis-free survival was observed in patients with pN0 and pN1 (vs. pN2+3) stage (p = 0.040) and with tumors characterized by low Ki-67LI (≤ 50% vs. > 50%) (p = 0.014). Patients with tumor androgen receptor immunonegativity (weak or lack of expression) or strong PTEN expression survived 3 years without metastases (p = 0.007). The results of our study suggest that androgen receptor and PTEN status might be considered as indicators of trastuzumab sensitivity.

BackgroundThe aim of the study was to investigate if parameters associated with human epidermal growth factor receptor type 2 (HER2) status (HER2 gene copy number, HER2/CEP17 ratio or polysomy of chromosome 17) are related to various biological features potentially responsible for trastuzumab resistance (PTEN, IGF-1R, MUC4, EGFR, HER3, HER4, and mutation status of PIK3CA) as well as their influence on survival of HER2-positive breast cancer patients treated with adjuvant chemotherapy and trastuzumab.Patients and methodsThe investigated group consisted of 117 patients with invasive ductal breast cancer (T≥1, N≥0, M0) with overexpression of HER2, who underwent radical surgery between 2007 and 2014. Status of ER, PR, and HER2 expression was retrieved from patients’ files. HER2 gene copy number was investigated by fluorescence in situ hybridization using PathVysion HER-2 DNA Probe Kit II. Expression of PTEN, IGF-1R, MUC4, EGFR, HER3, and HER4 was assessed immunohistochemically on formalin-fixed paraffin-embedded tissue sections. PIK3C mutation status was determined by qPCR analysis.ResultsOverexpression of HER2 protein (IHC 3+) and ER negativity corresponded to higher HER22 copy number and HER2/CEP17 ratio (.<0.001). Tumors with polysomy were characterized by higher HER22 gene copy number but lower HER2/CEP17p ratio (p<0.026, p<0.001). Patients with tumors featuring HER3 immunonegativity or low HER2/CEP17 ratio (#4) were characterized by 100% metastasis-free survival (.=0.018, p=0.062).ConclusionPresence of both unfavorable factors, ie, HER3 expression and high HER2/CEP17 ratio, allowed to distinguish a group of patients with worse prognosis (.=0.001).

Aim: Resistance to trastuzumab (which is a standard therapy for breast cancer patients with HER2 overexpression) is associated with higher risk of progression or cancer death, and might be related to activation of signalling cascades (PI3K/AKT/mTOR, Ras/Raf/MAPK) and decreased level of their inhibitors.Material and methods: Formalin-fixed paraffin-embedded tumour specimens from 118 HER2-overexpressing breast cancer patients treated with radical local therapy and trastuzumab in adjuvant setting were used for the assessment of: (1) PIK3CA gene mutations (p.H1047R and p.E545K) by qPCR, and (2) expression of Ki-67, EGFR, MUC4, HER3 and PTEN by immunohistochemistry.Results: Lower Ki-67LI was observed in EGFR-immunonegative and in PTEN-immunopositive tumours. MUC4-immunonegative tumours more frequently were PTEN- and HER3-immunonegative. Favourable metastasis-free survival was observed in patients with tumours characterized by Ki-67LI≤50% (p=0.027), HER3 immunonegativity or PTEN immunopositivity (vs. tumours with HER3 expression and lack of PTEN expression, p=0.043), additionally, the trend was observed for patients with pN0+pN1 pathological tumour stage (vs. pN2+pN3) (p=0.086). Cox model revealed that independent negative prognostic factors were: (i) Ki-67LI>50% (p=0.014, RR=4.6, 95% CI 1.4-15.4), (ii) HER3 immunopositivity together with PTEN immunonegativity (p=0.034, RR=3.7, 95% CI 1.1-12.5).Conclusion: The results of our study suggest that combined analysis of HER3 and PTEN expression might bring information on trastuzumab sensitivity in the group of HER2-positive breast cancer patients treated with trastuzumab in adjuvant setting.

Lapatinib is a HER1 and HER2 tyrosine kinase inhibitor (TKI) approved in second line treatment of advanced or metastatic breast cancer following progression on trastuzumab-containing therapy. Biomarkers for activity of lapatinib and other TKIs are lacking.Formalin-fixed, paraffin-embedded primary tumor samples were obtained from 189 HER2-positive patients treated with lapatinib plus capecitabine following progression on trastuzumab. The HERmark® Breast Cancer Assay was used to quantify HER2 protein expression. HER3 and p95HER2 protein expression was quantified using the VeraTag® technology.Overall survival (OS) was inversely correlated with HER2 (HR = 1.9/log; P = 0.009) for patients with tumors above the cut-off positivity level by the HERmark assay. OS was significantly shorter for those with above median HER2 levels (HR = 1.7; P = 0.015) and trended shorter for those below the cut-off level of positivity by the HERmark assay (HR = 1.7; P = 0.057) compared to cases with moderate HER2 overexpression. The relationship between HER2 protein expression and OS was best captured with a U-shaped parabolic function (P = 0.004), with the best prognosis at moderate levels of HER2 protein overexpression. In a multivariate model including HER2, increasing p95HER2 expression was associated with longer OS (HR = 0.35/log; P = 0.027). Continuous HER3 did not significantly correlate with OS.Patients with moderately overexpressed HER2 levels and high p95HER2 expression may have best outcomes while receiving lapatinib following progression on trastuzumab. Further study is warranted to explore the predictive utility of quantitative HER2 and p95HER2 in guiding HER2-directed therapies.

Introduction.The aim of this prospective study was to estimate the perception and popularity of complementary and alternative medicine (CAM) subtypes and the reasons for usage among adult Polish cancer patients. Material and methods. The validated questionnaire was conducted among 310 patients. 24.1% of the patients used CAM during their oncological treatment. Risk factors for CAM usage were: female gender, university degree and radical treatment. The most common reasons for CAM usage were: boosting the immune system (46.1%), improving well-being/ counteracting the ill effects of cancer and its treatment (40.8%). The average level of satisfaction with CAM was high (≥3/5 on a Likert scale). Nearly half of the patients (46.6%) admitted not informing their doctors about their CAM usage. Conclusions. The growing popularity and heterogeneity of CAM methods make it an important issue for patient-doctor relations in Poland and other Central European countries. The results of this study indicate what topics should be covered while introducing patient education programs.

Numerous studies have shown that cancer development and metastasis formation are complex processes which involve not only cancer cells but also their interaction with selected components of tumor stroma. According to the seed and soil hypothesis, a permissive microenvironment (soil) facilitates growth of metastatic cancer cells (seed) in secondary sites. It was shown that stromal components (including cancerassociated fibroblasts, CAFs) can travel together with metastatic cells from the primary to secondary site. Moreover, co-traveling stromal cells can increase the viability of circulating metastatic cancer cells and provide them with an early growth advantage (1). It was also shown that CAFs promote tumor invasion by exerting a physical force on cancer cells, enabling them to escape from the primary site (2) . The identification of CAFs in peripheral blood from patients with metastatic breast cancer confirms the hypothesis suggesting co-travel of stromal and cancer cells during formation of metastases (3).In vitro studies and research based on animal models suggest a very important role of the cancer stroma in tumor progression (1, 4). The above phenomena were confirmed by studies in which the following stroma-related parameters were found to be of prognostic significance: (i) tumor-tostroma ratio (5-7); (ii) the type of tumor stroma (fibroblastdominant vs. lymphatic-dominant vs. collagen-dominant) (8-10); (iii) the presence of podoplanin-positive CAFs (ppCAFs) (11)(12)(13)(14) . Furthermore, it was suggested that CAFs might contribute to: (i) tumor initiation; (ii) proliferation, migration and invasiveness of cancer cells; (iii) tumor angiogenesis/lymphangiogenesis; (iv) tumor-induced inflammation; (v) metabolic reprogramming of the tumor microenvironment; and (vi) therapeutic resistance (4). Among many CAF-related proteins, podoplanin is one of the most intensively studied (8,9,(15)(16)(17) . Among breast cancer immunophenotypes, the human epidermal growth factor receptor 2 (HER2)-overexpressing subtype is the one in which ppCAFs were found to be relatively frequent (11).This prompted us to analyze: (i) the status of ppCAFs in primary tumor and paired synchronous lymph node metastases (LNMs); (ii) relation between ppCAFs in tumor