The relevance of circulating epithelial tumor cells (CETC) for therapy monitoring during neoadjuvant (primary systemic) chemotherapy in breast cancer

Chemotherapy-induced metastasis: molecular mechanisms and clinical therapies

Chemotherapy, the most widely accepted treatment for malignant tumors, is dependent on cell death induced by various drugs including antimetabolites, alkylating agents, mitotic spindle inhibitors, antitumor antibiotics, and hormonal anticancer drugs. In addition to causing side effects due to non-selective cytotoxicity, chemotherapeutic drugs can initiate and promote metastasis, which greatly reduces their clinical efficacy. The knowledge of how they induce metastasis is essential for developing strategies that improve the outcomes of chemotherapy. Herein, we summarize the recent findings on chemotherapy-induced metastasis and discuss the underlying mechanisms including tumor-initiating cell expansion, the epithelial-mesenchymal transition, extracellular vesicle involvement, and tumor microenvironment alterations. In addition, the use of combination treatments to overcome chemotherapy-induced metastasis is also elaborated.

Heterogeneous circulating tumor cells correlate with responses to neoadjuvant chemotherapy and prognosis in patients with locally advanced breast cancer

Neoadjuvant chemotherapy (NCT) is the standard treatment for patients with locally advanced breast cancer (LABC). The predictive value of heterogeneous circulating tumor cells (CTCs) in NCT response has not been determined. All patients were staged as LABC, and blood samples were collected at the time of biopsy, and after the first and eighth NCT courses. Patients were divided into High responders (High-R) and Low responders (Low-R) according to Miller-Payne system and changes in Ki-67 levels after NCT treatment. A novel SE-i·FISH strategy was applied to detect CTCs. Heterogeneities were successfully analyzed in patients undergoing NCT. Total CTCs increased continuously and were higher in Low-R group, while in High-R group, CTCs increased slightly during NCT before returning to baseline levels. Triploid and tetraploid chromosome 8 increased in Low-R but not High-R group. The number of small CTCs in Low-R group increased significantly until the last sample, however, remained constant in High-R group. The patients with more CTCs had shorter PFS and OS than those with less CTCs after the eighth course of NCT. Total CTCs following NCT could predict patients' responses. More detailed characterizations of CTC blood profiles may improve predictive capacity and treatments of LABC.

Liquid biopsy leads to a paradigm shift in the treatment of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most cancers. Its 5-year survival rate is very low. The recent induction of neoadjuvant chemotherapy and improvements in chemotherapy for patients with pancreatic cancer have resulted in improved survival outcomes. However, the prognosis of pancreatic cancer is still poor. To dramatically improve the prognosis, we need to develop more tools for early diagnosis, treatment selection, disease monitoring, and response rate evaluation. Recently, liquid biopsy (circulating free DNA, circulating tumor DNA, circulating tumor cells, exosomes, and microRNAs) has caught the attention of many researchers as a new biomarker that is minimally invasive, confers low-risk, and displays an overall state of the tumor. Thus, liquid biopsy does not employ the traditional difficulties of obtaining tumor samples from patients with advanced PDAC to investigate their molecular biological status. In addition, it allows for long-term monitoring of the molecular profile of tumor progression. These could help in identifying tumor-specific alterations that use the target structure for tailor-made therapy. Through this review, we highlighted the latest discoveries and advances in liquid biopsy technology in pancreatic cancer research and showed how it can be applied in clinical practice.

Quantitative Phase Imaging Detecting the Hypoxia-Induced Patterns in Healthy and Neoplastic Human Colonic Epithelial Cells

Hypoxia is a frequent phenomenon during carcinogenesis and may lead to functional and structural changes in proliferating cancer cells. Colorectal cancer (CRC) is one of the most common neoplasms in which hypoxia is associated with progression. The aim of this study was to assess the optical parameters and microanatomy of CRC and the normal intestinal epithelium cells using the digital holotomography (DHT) method. The examination was conducted on cancer (HT-29, LoVo) and normal colonic cells (CCD-18Co) cultured in normoxic and hypoxic environments. The assessment included optical parameters such as the refractive index (RI) and dry mass as well as the morphological features. Hypoxia decreased the RI in all cells as well as in their cytoplasm, nucleus, and nucleoli. The opposite tendency was noted for spheroid-vesicular structures, where the RI was higher for the hypoxic state. The total volume of hypoxic CCD-18Co and LoVo cells was decreased, while an increase in this parameter was observed for HT-29 cells. Hypoxia increased the radius and cell volume, including the dry mass of the vesicular content. The changes in the optics and morphology of hypoxic cells may suggest the possibility of using DHT in the detection of circulating tumor cells (CTCs).

Microtubule disruption reduces metastasis more effectively than primary tumor growth

Clinical cancer imaging focuses on tumor growth rather than metastatic phenotypes. The microtubule-depolymerizing drug, Vinorelbine, reduced the metastatic phenotypes of microtentacles, reattachment and tumor cell clustering more than tumor cell viability. Treating mice with Vinorelbine for only 24 h had no significant effect on primary tumor survival, but median metastatic tumor survival was extended from 8 to 30 weeks. Microtentacle inhibition by Vinorelbine was also detectable within 1 h, using tumor cells isolated from blood samples. As few as 11 tumor cells were sufficient to yield 90% power to detect this 1 h Vinorelbine drug response, demonstrating feasibility with the small number of tumor cells available from patient biopsies. This study establishes a proof-of-concept that targeted microtubule disruption can selectively inhibit metastasis and reveals that existing FDA-approved therapies could have anti-metastatic actions that are currently overlooked when focusing exclusively on tumor growth.

Circulating tumor cells may serve as a supplement to RECIST in neoadjuvant chemotherapy of patients with locally advanced breast cancer

BACKGROUND

Circulating tumor cells (CTCs) have been shown to be associated with the response to neoadjuvant chemotherapy (NCT) and the prognosis of locally advanced breast cancer (LABC) patients. Our study aimed to investigate whether the change of CTC status during NCT could serve as a supplement to the Response Evaluation Criteria in Solid Tumors (RECIST) in the treatment and evaluation of LABC patients.

METHODS

6 ml of blood samples were collected before NCT, after the first cycle of NCT and after the completion of NCT, respectively. According to the change of CTC number during NCT, the patients were divided into "CTC low-response (low-R)" group and "CTC high-response (high-R)" group. Survival data of each group of patients were obtained through long-term follow-up.

RESULTS

A total of 35 patients diagnosed with LABC were enrolled. The median follow-up for distant metastasis was 27 months (range 7-36 months). There was no significant difference in distant metastasis-free survival (DMFS) between PR/CR group and PD/SD group (P = 0.0914), while CTC low-R group had a worse DMFS than CTC high-R group (P = 0.0199). In PR/CR subgroup, patients with CTC low-R showed a lower DMFS compared with those with CTC high-R (P = 0.0159). However, in PD/SD subgroup, there was no significant difference in DMFS between CTC low-R and CTC high-R group (P = 0.7521). In terms of assessing response to NCT, CTC change or RECIST classification alone had an AUC of 0.533 (95% CI 0.277-0.790) and 0.700 (95% CI 0.611-0.789), respectively. When combining the two, the AUC slightly increased to 0.713 (95% CI 0.532-0.895).

CONCLUSION

The change of CTC number during NCT has a potential to serve as a supplement to RECIST in the assessment of NCT efficacy and the prognosis of LABC patients.

Plasma Proteome Signature to Predict the Outcome of Breast Cancer Patients Receiving Neoadjuvant Chemotherapy

The plasma proteome of 51 non-metastatic breast cancer patients receiving neoadjuvant chemotherapy (NCT) was prospectively analyzed by high-resolution mass spectrometry coupled with nano-flow liquid chromatography using blood drawn at the time of diagnosis. Plasma proteins were identified as potential biomarkers, and their correlation with clinicopathological variables and survival outcomes was analyzed. Of 51 patients, 20 (39.2%) were HR+/HER2-, five (9.8%) were HR+/HER2+, five (9.8%) were HER2+, and 21 (41.2%) were triple-negative subtype. During a median follow-up of 52.0 months, there were 15 relapses (29.4%) and eight deaths (15.7%). Four potential biomarkers were identified among differentially expressed proteins: APOC3 had higher plasma concentrations in the pathological complete response (pCR) group, whereas MBL2, ENG, and P4HB were higher in the non-pCR group. Proteins statistically significantly associated with survival and capable of differentiating low- and high-risk groups were MBL2 and P4HB for disease-free survival, P4HB for overall survival, and MBL2 for distant metastasis-free survival (DMFS). In the multivariate analysis, only MBL2 was a consistent risk factor for DMFS (HR: 9.65, 95% CI 2.10-44.31). The results demonstrate that the proteomes from non-invasive sampling correlate with pCR and survival in breast cancer patients receiving NCT. Further investigation may clarify the role of these proteins in predicting prognosis and thus their therapeutic potential for the prevention of recurrence.

Circulating Tumor Cells in Esophageal Squamous Cell Carcinoma - Mini Review

Esophageal cancer has high incidence and mortality rates and a low five-year survival rate of <15% owing to its strong capabilities of invasion, relapse and metastasis. The classic view holds that metastasis and diffusion is an advanced event during cancer progression, but recent studies show that distant diffusion of primary cancer cells may actually be an early event. Detection of circulating tumor cells (CTCs) in the circulation may indicate tumor spread, so CTCs are considered to be the key factor of metastatic cascade. In recent years, despite research progress on CTCs, there is a lack of systematic and important evidence to confirm the diagnostic, monitoring and prognostic values of CTCs in esophageal squamous cell carcinoma (ESCC). In this review, we clarify the relationship between CTC values and ESCC and provide more reliable evidence to improve the management and treatment of ESCC.

Characterization of circulating tumor cells in early breast cancer patients receiving neoadjuvant chemotherapy

Background and Aims:

The aim of this study was to characterize circulating tumor cells (CTCs) during neoadjuvant chemotherapy (NACT) in early and locally advanced breast cancer (LABC) patients. Using ultrasound, tumor volume measurement was compared with the presence and the molecular nature of CTCs over multiple time intervals corresponding to treatment periods.

Methods:

A total of 20 patients diagnosed with breast cancer (BC) of different histotypes were monitored during the NACT period and in the follow-up period (~5 years). Peripheral blood for CTCs (n = 115) was taken prior to NACT, after two to three chemotherapy cycles, after the completion of NACT (before surgery) and at some time points during adjuvant therapy. CTCs were enriched using a size-based filtration method (MetaCell®) capturing viable cells, which enabled vital fluorescence microscopy. A set of tumor-associated (TA) genes and chemoresistance-associated (CA) genes was analyzed by qPCR in the enriched CTC fractions.

Results:

The analysis of tumor volume reduction after administration of anthracyclines (AC) and taxanes (TAX) during NACT showed that AC therapy was responsive in 60% (12/20) of tumors, whereas TAX therapy was responsive in 30% (6/20; n.s.). After NACT, CTCs were still present in 70.5% (12/17) of patients (responders versus non-responders, 61.5% versus 100%; not significant).

In triple-negative BC (TNBC) patients (n = 8), tumor volume reduction was observed in 75% cases. CTCs were significantly reduced in 42.9% of all HER2-negative BC patients. In HER2+ tumors, CTC reduction was reported in 16.6% only. Relapses were also more prevalent in the HER2-positive patient group (28.5 versus 66.6%).

During NACT, the presence of CTCs (three tests for each patient) identified patients with relapses and indicated significantly shorter progression-free survival (PFS) rates (p = 0.03). Differentiation between progressive disease and non-progressive disease was obtained when the occurrence of excessive expression for CA genes in CTCs was compared (p = 0.024). Absence of tumor volume reduction was also significantly indicative for progressive disease (p = 0.0224).

Disseminated CTCs in HER2-negative tumors expressed HER2 in 29% of samples collected during the overall follow-up period (16/55), and in 32% of samples during the follow-up of NACT (10/31). The change accounted for 78.5% of HER2-negative patients (11/14) in total, and 63.6% of the conversion cases occurred during NACT (7/11). For the remaining four patients (36.3%), conversion to HER2+ CTCs occurred later during adjuvant therapy. We believe there is the possibility of preventing further progression by identifying less responsive tumors during NACT using CTC monitoring, which could also be used effectively during adjuvant therapy.

Liquid Biopsy: A New Tool for Overcoming CDKi Resistance Mechanisms in Luminal Metastatic Breast Cancer

Breast cancer (BC) is the most common cancer diagnosed in women worldwide. Approximately 70% of BC patients have the luminal subtype, which expresses hormone receptors (HR+). Adjuvant endocrine treatments are the standard of care for HR+/HER2− BC patients. Over time, approximately 30% of those patients develop endocrine resistance and metastatic disease. Cyclin-dependent kinase inhibitors (CDKi), in combination with an aromatase inhibitor or fulvestrant, have demonstrated superior efficacies in increasing progression-free survival, with a safe toxicity profile, in HR+/HER2− metastatic BC patients. CDKi blocks kinases 4/6, preventing G1/S cell cycle transition. However, not all of the patients respond to CDKi, and those who do respond ultimately develop resistance to the combined therapy. Studies in tumour tissues and cell lines have tried to elucidate the mechanisms that underlie this progression, but there are still no conclusive data. Over the last few years, liquid biopsy has contributed relevant information. Circulating tumour materials are potential prognostic markers for determining patient prognosis in metastatic luminal BC, for monitoring disease, and for treatment selection. This review outlines the different studies performed using liquid biopsy in patients with HR+ metastatic BC treated with CDKi plus endocrine therapy. We mainly focus on those studies that describe the possible resistance mechanisms in circulating tumour-derived material.

Conventional versus reverse sequence of neoadjuvant epirubicin/cyclophosphamide and docetaxel: sequencing results from ABCSG-34

BACKGROUND

Preoperative chemotherapy containing anthracyclines and taxanes is well established in early-stage breast cancer. Previous studies have suggested that the chemotherapy sequence may matter but definitive evidence is missing. ABCSG trial 34 evaluated the activity of the MUC1 vaccine tecemotide when added to neoadjuvant treatment; the study provided the opportunity for the second randomisation to compare two different anthracycline/taxane sequences.

METHODS

HER2-negative early-stage breast cancer patients were recruited to this randomised multicentre Phase 2 study. Patients in the chemotherapy cohort (n = 311) were additionally randomised to a conventional or reversed sequence of epirubicin/cyclophosphamide and docetaxel. Residual cancer burden (RCB) with/without tecemotide was defined as primary study endpoint; RCB in the two chemotherapy groups was a key secondary endpoint.

RESULTS

No significant differences in terms of RCB 0/I (40.1% vs. 37.2%; P = 0.61) or pathologic complete response (pCR) rates (24.3% vs. 25%, P = 0.89) were observed between conventional or reverse chemotherapy sequence. No new safety signals were reported, and upfront docetaxel did not result in decreased rates of treatment delay or discontinuation.

CONCLUSION

Upfront docetaxel did not improve chemotherapy activity or tolerability; these results suggest that upfront neoadjuvant treatment with anthracyclines remains a valid option.

Influence of adjuvant radiotherapy on circulating epithelial tumor cells and circulating cancer stem cells in primary non-metastatic breast cancer

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CETCs have the same molecular properties as the cells in the primary tumor.

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Circulating cancer stem cells can be successfully identified in the blood of breast cancer patients and monitored during RT.

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Patients after neoadjuvant chemotherapy had the highest number of CETCs prior to RT but the CETC counts decreased significantly during RT indicating that this group of patients could most likely benefit from adjuvant RT.

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Increase in cCSC numbers during RT could be a predictor for early recurrence of cancer disease.

Background

: There is an unmet need to identify biomarkers that directly reflect response to adjuvant radiotherapy (RT). Circulating epithelial tumor cells (CETCs) represent the liquid component of solid tumors and are responsible for metastatic relapse. CETC subsets with cancer stem cell characteristics, circulating cancer stem cells (cCSCs), play a pivotal role in the metastatic cascade. Monitoring the most aggressive subpopulation of CETCs could reflect the aggressiveness of the remaining tumor burden. There is limited data on the detection and monitoring changes in CETC and cCSC numbers during RT in early breast cancer.

Methods

: CETC numbers were analyzed prior to, at midterm and at the end of RT in 52 primary non-metastatic breast cancer patients. Hormone receptor status was determined in CETCs prior to and at the end of RT. For the identification of cCSCs cell suspensions from the peripheral blood of patients were cultured in vitro under conditions favoring growth of tumorspheres.

Results

: Hormone receptor status in CETCs before RT was comparable to that in primary tumor tissue. Prior to RT numbers of CETCs correlated with aggressiveness of primary tumors. cCSCs could be successfully identified and monitored during RT. Prior to RT patients treated with neoadjuvant chemotherapy had significantly higher numbers of CETCs and tumorspheres compared to patients after adjuvant chemotherapy. During RT, the number of CETCs decreased continuously in patients after neoadjuvant chemotherapy but not after adjuvant chemotherapy.

Conclusion

: Monitoring the number of CETCs and the CETC subset with cancer stem cell properties during RT may provide additional clinically useful prognostic information.

Analysis of the serial circulating tumor cell count during neoadjuvant chemotherapy in breast cancer patients

We evaluated the prognostic implications of the circulating tumor cell (CTC) count in non-metastatic, HER2-negative breast cancer patients who failed to achieve pathologic complete response (pCR) after neoadjuvant chemotherapy (NCT). A total of 173, non-metastatic breast cancer patients treated with NCT were prospectively enrolled. CTCs were obtained from blood drawn pre-NCT and post-NCT using a SMART BIOPSY SYSTEM isolation kit (Cytogen Inc., Seoul, Korea) with immunofluorescence staining. Excluding 26 HER2-positive patients, Relapse-free survival (RFS) and overall survival (OS) related to the CTC count and the association of the CTC count with the treatment response to given therapy were analyzed in 147 HER2-negative patients. Among 147 HER2-negative patients, 28 relapses (19.0%) and 13 deaths (8.8%, all breast cancer-specific) were observed during a median follow-up of 37.3 months. One hundred and seven patients (72.8%) were hormone receptor-positive, and 40 patients (27.2%) had triple-negative breast cancer (TNBC). One or more CTCs were identified in 88 of the 147 patients (59.9%) before NCT and 77 of the 134 patients (52.4%) after NCT. In the entire HER2-negative patient cohort, the initial nodal status was the most significant factor influencing RFS and OS. In TNBC, 11 patients (27.5%) achieved pCR and patients that failed to achieve pCR with ≥ 5 CTCs after NCT, showed worse RFS (HR, 10.66; 95% CI, 1.80–63.07; p = 0.009) and OS (HR, 14.00; 95% CI, 1.26–155.53; p = 0.032). The patients with residual tumor and a high number of the CTCs after NCT displayed the worse outcome. These findings could provide justification to launch a future, well designed trial with longer follow-up data to obtain regulatory approval for clinical use of the assay, especially for the ER-positive, HER2-negative breast cancer subset.

Rare Treatment for a Rare Tumor: Cryoablation of a Granular Cell Tumor

Background

Granular cell tumors (GCTs) or Abrikossoff's tumors are rare neoplasms known to originate from Schwann cells in the peripheral nervous system. These lesions are usually benign; malignancy only occurs in 1-2% of cases. Surgical resection is the traditional treatment method for GCTs, but it poses several risks and disadvantages related to the surgical incompatibility of the patient, the extended recovery time, and the chance of relapse. Cryoablation is becoming an increasingly favored method of treatment for tumors, both benign and malignant, due to its minimal invasiveness, natural analgesic properties, and ability to stimulate antitumor immunity. Cryoablation may contribute to the prevention of secondary and metastatic tumor growth in cases of malignancy by preserving tumor-associated antigen molecules for recognition by cell-mediated immunity.

Methods

This article describes a novel method for GCT treatment using cryoablation. This technique exposes tumor tissue to extreme cold temperatures, effectively destroying tumor cells by irreversibly compromising their plasma membranes. To our knowledge, this is the first report in the literature of cryoablative techniques being used for GCT.

Results

Cryoablation of this mass was successful with no complications. CT images during the procedure demonstrated circumferential coverage of the entire lesion with no injury to the surrounding tissues.

Conclusion

Cryoablation can be used as an alternative to surgical intervention to treat malignant GCTs. This procedure is minimally invasive, less painful, and potentially effective in promoting antitumor immunity.

Non-Metastatic Esophageal Adenocarcinoma: Circulating Tumor Cells in the Course of Multimodal Tumor Treatment

BACKGROUND

Isolation of circulating tumor cells (CTC) holds the promise to improve response-prediction and personalization of cancer treatment. In this study, we test a filtration device for CTC isolation in patients with non-metastatic esophageal adenocarcinoma (EAC) within recent multimodal treatment protocols.

METHODS

Peripheral blood specimens were drawn from EAC patients before and after neoadjuvant chemotherapy (FLOT)/chemoradiation (CROSS) as well as after surgery. Filtration using ScreenCell^® devices captured CTC for cytologic analysis. Giemsa-stained specimens were evaluated by a cytopathologist; the cut-off was 1 CTC/specimen (6 mL). Immunohistochemistry with epithelial (pan-CK) and mesenchymal markers (vimentin) was performed.

RESULTS

Morphologically diverse malignant CTCs were found in 12/20 patients in at least one blood specimen. CTCs were positive for both vimentin and pan-CK. More patients were CTC positive after neoadjuvant therapy (6/20 vs. 9/15) and CTCs per/ml increased in most of the CTC-positive patients. After surgery, 8/13 patients with available blood specimens were still CTC positive. In clinical follow-up, 5/9 patients who died were CTC-positive.

CONCLUSIONS

Detection of CTC by filtration within multimodal treatment protocols of non-metastatic EAC is feasible. The rate of CTC positive findings and the quantity of CTCs changes in the course of multimodal neoadjuvant chemoradiation/chemotherapy and surgery.

Circulating Tumour Cells in Predictive Molecular Pathology: Focus on Drug-Sensitive Assays and 3D Culture

Molecular cytopathology is a rapidly evolving field of cytopathology that provides biological information about the response to personalised therapy and about the prognosis of neoplasms diagnosed on cytological samples. Biomarkers such as circulating tumour cells and circulating tumour DNA are increasingly being evaluated in blood and in other body fluids. Such liquid biopsies are non-invasive, repeatable, and feasible also in patients with severe comorbidities. However, liquid biopsy may be challenging due to a low concentration of biomarkers. In such cases, biomarkers can be detected with highly sensitive molecular techniques, which in turn should be validated and integrated in a complex algorithm that includes tissue-based molecular assessments. The aim of this review is to provide the cytopathologist with practical information that is relevant to daily practice, particularly regarding the emerging role of circulating tumour cells in the field of predictive molecular pathology.

Circulating tumor cells with karyotyping as a novel biomarker for diagnosis and treatment of nasopharyngeal carcinoma

Background

Circulating tumor cells (CTCs) have been considered great clinical significance in various cancers. However, it remains unknown that how is the role of CTCs in patients with nasopharyngeal carcinoma (NPC). We investigated the value of CTCs enumeration and karyotyping in NPC.

Methods

In the present study, we applied integrated subtraction enrichment and immunostaining-fluorescence in situ hybridization (SE-iFISH) automatic testing system to detect and characterize CTCs of NPC patients. Enumeration and aneuploidy of chromosome 8 in CTCs were examined in various stages of patients with NPC. The changes of CTCs number and karyotyping post to chemotherapy were investigated in NPC.

Results

CTCs were detected by SE-iFISH in 46 out of 50 pre-treatment NPC patients, and performed a positive rate of 92.0%. No significant association was found between disease staging and CTCs detection rate. CTCs number constantly increased with TNM stage rising (from stage II to stage IV) no matter in newly diagnosed patients without distant metastasis (M0) and relapsed or distant metastatic patients. The number of CTCs decreased after treatment in patients with partial response (PR), while increased in patients with progressive disease or stable disease (PD/SD). More interestingly, CTCs karyotyping indicated that aneuploidy of chromosome 8 in CTCs was dramatically related to chemotherapeutic efficacy in NPC. Positive correlation was found between CTCs count and plasma EBV DNA level of NPC patients.

Conclusions

CTCs could be detected in various stages of NPC patients using SE-iFISH. CTCs number could indicate the severity degree of disease in NPC. Dynamically monitoring the variations in CTCs number may predict chemotherapy efficacy during treatment. CTCs karyotyping is related to the sensibility of chemotherapy and drug resistance, and karyotyping of CTCs might predict therapeutic efficacy and evaluate chemo-resistance in NPC. CTCs could be used as a monitoring indicator in the fields of treatment, diagnosis and follow-up of NPC.

The Value of Monitoring the Behavior of Circulating Tumor Cells at the End of Endocrine Therapy in Breast Cancer Patients

After five years of endocrine therapy, patients with ER+ (estrogen receptor positive) breast cancer face the question of the benefit of further treatment. Ten years of endocrine therapy has been demonstrated to improve survival compared to five years. However, the individual benefit of continuation remains unclear. Therefore, markers for predicting benefit from endocrine treatment and extended endocrine treatment are desperately needed. In this study the dynamics over time of the tumor cells circulating in peripheral blood of patients, circulating tumor cells/ circulating epithelial tumor cells (CTC/CETC), as the systemic part of the tumor were investigated in 36 patients with ER+ primary breast cancer. CTC/CETCs were monitored serially during and after endocrine therapy. After termination of endocrine therapy 12 patients showed an increase in CTC/CETCs, with 8 of 12 suffering relapse. No change or a reduction was observed in 24 patients, with 2 of 24 suffering relapse. Initial tumor size was marginally prognostic (p = 0.053) but not nodal status nor the mere number of CTC/CETCs. Only the trajectory of CTC/CETCs was a statistically significant predictor of relapse free survival (increasing cell numbers: mean = 940 days vs. stable/decreasing cell numbers mean not reached). Individual cases demonstrated that an increase of CTC/CETCs after discontinuation of tamoxifen therapy could be stopped by resuming the endocrine therapy.

Evaluation of Anti-Metastatic Potential of the Combination of Fisetin with Paclitaxel on A549 Non-Small Cell Lung Cancer Cells

The identification and development of new agents with a therapeutic potential as well as novel drug combinations are gaining the attention of scientists and clinicians as a plausible approach to improve therapeutic regimens for chemoresistant tumors. We have recently reported that the flavonoid fisetin (FIS), at physiologically attainable concentrations, acts synergistically with clinically achievable doses of paclitaxel (PTX) to produce growth inhibitory and pro-death effects on A549 human non-small cell lung cancer (NSCLC) cells. To further investigate a potential therapeutic efficacy of the combination of fisetin with paclitaxel, we decided to assess its impact on metastatic capability of A549 cells as well as its toxicity toward normal human lung fibroblast. Cell viability, cell migration, and invasion were measured by thiazolyl blue tetrazolium bromide (MTT) assay, wound healing assay, and Transwell chamber assay, respectively. The expression of metastasis-related genes was assessed with quantitative reverse transcriptase real-time polymerase chain reaction (qRT-PCR). Actin and vimentin filaments were examined under the fluorescence microscope. The combination of FIS and PTX significantly reduced cancer cell migration and invasion, at least partially, through a marked rearrangement of actin and vimentin cytoskeleton and the modulation of metastasis-related genes. Most of these effects of the combination treatment were significantly greater than those of individual agents. Paclitaxel alone was even more toxic to normal cells than the combination of this drug with the flavonoid, suggesting that FIS may provide some protection against PTX-mediated cytotoxicity. The combination of FIS and PTX is expected to have a synergistic anticancer efficacy and a significant potential for the treatment of NSCLC, however, further in vitro and in vivo studies are required to confirm this preliminary evidence.

Establishment and Application of Prostate Cancer Circulating Tumor Cells in the Era of Precision Medicine

Prostate cancer (PC) is the second most common cancer in men and is the fifth leading cause of cancer-related deaths worldwide. Additionally, there is concern for overdiagnosis and overtreatment of PC. Thus, selection of an appropriate candidate for active surveillance as well as more accurate and less invasive tools for monitoring advanced PC is required. Circulating tumor cells (CTCs) have emerged as a liquid biopsy tool; there have been several reports on its role, technologies, and applications to various cancers, including PC. Liquid biopsy using CTCs has been gaining attention as a minimal invasive tool for investigation of biomarkers and for prognosis and assessment of response to therapies in patients with PC. Because of the lower invasiveness of liquid biopsy using CTCs, it can be performed more frequently; accordingly, personalized disease status can be successively determined at serial time points. CTC analysis enables detection of genomic alterations, which is drug-targetable, and it is a potential tool for monitoring response to therapeutic agents in patients with PC. This review focuses on the characteristics, technologies for analysis, and advantages and disadvantages of CTCs as a liquid biopsy tool and their application in PC. Finally, we propose future directions of CTCs.

Cytoskeletal organization in microtentacles

Microtentacles are thin, flexible cell protrusions that have recently been described and whose presence enhances efficient attachment of circulating cells. They are found on circulating tumor cells and can be induced on a wide range of breast cancer cell lines, where they are promoted by factors that either stabilize microtubules or destabilize the actin cytoskeleton. Evidence suggests that they are relevant to the metastatic spread of cancer, so understanding their structure and formation may lead to useful therapies. Microtentacles are formed by microtubules and contain vimentin intermediate filaments, but beyond this, there is little information about their ultrastructure. We have used electron microscopy of high pressure frozen sections and tomography of cryo-prepared intact cells, along with super resolution fluorescence microscopy, to provide the first ultrastructural insights into microtubule and intermediate filament arrangement within microtentacles. By scanning electron microscopy it was seen that microtentacles form within minutes of addition of drugs that stabilize microtubules and destabilize actin filaments. Mature microtentacles were found to be well below one micrometer in diameter, tapering gradually to below 100nm at the distal ends. They also contained frequent branches and bulges suggestive of heterogeneous internal structure. Super resolution fluorescence microscopy and examination of sectioned samples showed that the microtubules and intermediate filaments can occupy different areas within the microtentacles, rather than interacting intimately as had been expected. Cryo-electron tomography of thin regions of microtentacles revealed densely packed microtubules and absence of intermediate filaments. The number of microtubules ranged from several dozen in some areas to just a few in the thinnest regions, with none of the regular arrangement found in axonemes. Improved understanding of the mechanism of microtentacle formation, as well as the resultant structure, will be valuable in developing therapies against metastasis, if the hypothesized role of microtentacles in metastasis is confirmed. This work provides a significant step in this direction.

PREDICTIVE CIRCULATING MARKERS FOR ANTHRACYCLINE CHEMOTHERAPY IN NON-METASTATIC BREAST CANCER

Anthracyclines are used in breast cancer both in early and advanced stages and their recommendation together with taxanes, either concurrently or sequentially, is debatable and individualized by phenotype. Circulating biomarkers have already been introduced in clinical practice for metastatic disease monitoring. We questioned whether it might be a role for these markers in neoadjuvant and adjuvant settings too and a general review was conducted. CK18 and CTC were found predictive for anthracycline related response in preoperative setting. Soluble E-cadherin is promising, a retrospective analysis showing a direct correlation with clinical response. CEA, CA 15-3 and HER2 ECD are not of interest for their predictive role.

Circulating tumor microemboli (CTM) and vimentin+ circulating tumor cells (CTCs) detected by a size-based platform predict worse prognosis in advanced colorectal cancer patients during chemotherapy

Background

Circulating tumor cells (CTCs) detected in peripheral blood (PB) of cancer patients can be identified as isolated CTCs and circulating tumor microemboli (CTM). This study aimed to evaluate the prognostic value of CTM detection and CTC phenotype in advanced colorectal cancer (CRC) patients during chemotherapy.

Methods

A size-based platform for CTC isolation was applied. PB samples (5 ml) from 98 advanced CRC patients during 2–6 cycles chemotherapy were collected for CTC detection, and CTC count was correlated to patient’s clinicopathological characteristics and clinical outcome. And CTC phenotype was measured by immunofluorescent staining and evaluate the predictive significance on survival in 32 CTCs-positive patients with advanced CRC.

Results

Forty-eight of 98 patients were CTCs-positive, including 18 CTM-positive patients, and CTC detection was positively correlated with lymphatic invasion (P = 0.049), TNM stage (P = 0.023), and serum CEA level (P = 0.014). Moreover, Kaplan–Meier survival and Cox regression analyses revealed that the presence of CTCs was an independent factor for poor PFS and OS (P < 0.05) in advanced CRC patients during chemotherapy, and CTM-positive patients had shooter survival than isolated CTCs-positive patients (P < 0.05). Furthermore, patients with vimentin+ isolated CTCs/CTM had shorter PFS and OS compared with CK+ CTCs (P < 0.05).

Conclusions

This study provided evidence that the presence of CTCs was positively correlated with poor prognosis, and furthermore, CTM and vimentin+ CTCs predicted poorer survival, which indicated that CTM and vimentin+ CTCs detected by a sensitive platform could be used to improve prognostic value of CTCs in advanced CRC patients under treatment.

Prognostic value of circulating tumor cells in advanced gastric cancer patients receiving chemotherapy

The identification of circulating tumor cells (CTCs) may provide important prognostic information in several types of solid tumors, including gastric cancer. The aim of this study was to investigate whether CTC count may be used to predict survival in patients with advanced gastric cancer treated with chemotherapy. The CELLection™ Epithelial Enrich kit was used to isolate and purify CTCs from samples of peripheral blood. Immunofluorescent staining was used for CTC counting. High CTC counts were associated with poor tumor differentiation and high serum CEA levels (P=0.021 and 0.005, respectively). After 3 months, 16 patients with decreasing CTC counts after the first cycle of chemotherapy obtained complete response, partial response or stable disease, while 13 patients with increasing CTC counts developed progressive disease. The patients with decreasing CTC counts also exhibited longer progression-free survival (PFS) (P≤0.001) and overall survival (OS) (P=0.002) compared with those with increasing CTC counts. Among all 59 patients, those with a CTC count of ≤2 cells/5 ml blood exhibited longer PFS (P≤0.001) and OS (P≤0.001) compared with those with a CTC count of >2 cells/5 ml blood. The multivariate analysis suggested that an increase of the CTC count after the first cycle of chemotherapy was only an independent prognostic marker of poor PFS (P=0.019). However, a baseline CTC count of >2 cells/5 ml blood was an independent poor prognostic marker for PFS (P=0.008) and OS (P=0.001) in all 59 patients. Our study suggested that patients with a low baseline CTC count or decrease of the CTC count after the first cycle of chemotherapy may benefit significantly from palliative chemotherapy. In conclusion, CTC count may be a good chemotherapy monitoring marker and an ideal prognostic marker for patients receiving palliative chemotherapy.

Enumeration and molecular characterization of circulating tumor cell using an in vivo capture system in squamous cell carcinoma of head and neck

Objective

Detection rate and isolation yield of circulating tumor cell (CTC) are low in squamous cell carcinoma of head and neck (SCCHN) with in vitro approaches due to limited sample volumes. In this study, we applied the CellCollector to capture CTC in vivo from peripheral blood.

Methods

In total, the study included 22 cases with 37 times of detection. All of the patients were newly diagnosed with locally advanced or metastatic SCCHN, including laryngocarcinoma (40.9%, 9/22) and hypopharyngeal carcinoma (59.1%, 13/22). All patients received CTC analysis before treatment. Three patients received induction chemotherapy. Sixteen patients received surgical therapy, of which 13 patients received postoperative detection. Two patients received both induction chemotherapy and surgery treatment. Patients underwent two successive CellCollector applications 24 h before and 7 d after surgical therapy. Nine healthy volunteers were enrolled as the control group. Epidermal growth factor receptor variant type III (EGFRVIII) expression was analyzed with fluorescent dye labeled antibody.

Results

With CellCollector isolation, 72.7% (16/22) of the patients were positive for ≥1 CTC (CTC; range, 1–17 cells) before treatments and 46.7% (7/15) of patients were CTC positive for ≥1 CTC (CTC; range, 1–29 cells) after surgical therapy. Moreover, the detection rate of CellCollector (82.4%, 14/17; CTC count range, 0–17) in advanced SCCHN (stage III–IV) was much higher than that in early stages (stage I–II, 40.0%, 2/5; CTC count range, 0–2) (P<0.05). EGFRVIII expression of CTC was also analyzed with fluorescence staining. One CTC^EGFRVIII-positive patient was detected from six CTC-positive patients, and the positive expression of EGFRVIII was also found in the tumor tissue of this patient.

Conclusions

In vivo detection of CTCs had high sensitivity in SCCHN, which might improve CTC application in clinic.

Change in number and size of circulating tumor cells with high telomerase activity during treatment of patients with gastric cancer

Detection of circulating tumor cells (CTCs) in peripheral blood is useful for estimating the prognosis of patients with cancer. We previously reported the detection of CTCs by OBP-401, a telomerase-specific, replication-selective, oncolytic adenoviral agent carrying the green fluorescent protein (GFP) gene. We demonstrated that the number of large (L)-GFP+ cells (≥7.735 µm in diameter) in peripheral blood samples correlated significantly with the prognosis of treatment-naïve gastric cancer patients, whereas the number of small (S)-GFP+ cells (<7.735 µm in diameter) did not. In the present study, we studied the change in the number of GFP+ cells during treatment, and analyzed the association between the number of GFP+ cells in blood samples and the outcome of patients. Peripheral blood samples were obtained from 37 gastric patients prior and subsequent to surgery (three samples per time point). Upon infection of blood cells with OBP-401, GFP+ cells of different sizes were counted and measured. The association between the number of GFP+ cells and surgical outcome was determined by statistical analysis. The median follow-up period after surgery was 39 months. Although the difference was not significant, patients with ≥6 L-GFP+ cells in preoperative blood samples had a lower relapse-free survival rate than patients with 0-5 L-GFP+ cells. There was no significant correlation between the number of L-GFP+ cells in postoperative blood samples and the prognosis of patients receiving adjuvant therapy. Although the difference was not significant, the number of S-GFP+ cells in samples from patients who had received postoperative chemotherapy was higher than in those who had not. The number of L-GFP+ cells was not significantly correlated with the relapse-free survival rate in gastric cancer patients who underwent surgery. The number of S-GFP+ cells was relatively high in samples from patients who had received postoperative chemotherapy.

Treatment of advanced solid tumours with NSAIDs: Correlation of quantitative monitoring of circulating tumour cells and positron emission tomography-computed tomography imaging

The detection and characterisation of tumour-derived circulating epithelial tumor cells (CETCs) or circulating tumor cells (CTCs) have been a main focus of basic oncological research over previous years. Numerous studies in the past decade have shown that CTCs are a promising tool for the estimation of the risk for metastatic relapse. The present observational study describes treatment results using tumour imaging and the quantification of CTCs. A group of 14 patients with advanced carcinomas was followed during their anticancer treatments. CTC numbers were serially detected and treatment success was estimated by positron emission tomography-computed tomography. A connection was found between tumour remission and a decreasing CTC count in 83%, a connection between stable disease and stable CTC numbers in 78% and a connection between progressive disease (PD) and an increase in CTC count in 50% of cases. In the patients with PD, an incomplete response was observed affecting the CTCs, but not the solid region of the tumour. As a result of this study, it may be concluded that patients with solid tumours benefit from serial quantification of CTCs in addition to imaging, as this combination of techniques provides a more sensitive result than imaging alone.

Circulating Tumor Cells

Circulating Tumor Cells (CTC) are shed from primary or secondary tumors. Prior studies have demonstrated that enumeration of CTC is a robust independent prognostic factor of progression free and overall survival in patients with early and metastatic breast cancer. CTC, as well as other circulating tumor markers, have the appealing advantages over tissue biopsy of (1) ease of collection, (2) serial evaluation, and (3) interrogation of the entire tumor burden instead of just a limited part of the tumor. Advances have been recently made in phenotyping and genotyping of CTC, which should provide insights into the predictive role of CTC for sensitivity or resistance to therapies. In addition, CTC phenotypic marker changes during the course of treatment may serve as pharmacodynamic monitoring tools. Therefore, CTC may be considered "liquid biopsies," providing prognostic and predictive clinical information as well as additional understanding of tumor heterogeneity.

Minimal residual disease in breast cancer: an overview of circulating and disseminated tumour cells

Within the field of cancer research, focus on the study of minimal residual disease (MRD) in the context of carcinoma has grown exponentially over the past several years. MRD encompasses circulating tumour cells (CTCs)—cancer cells on the move via the circulatory or lymphatic system, disseminated tumour cells (DTCs)—cancer cells which have escaped into a distant site (most studies have focused on bone marrow), and resistant cancer cells surviving therapy—be they local or distant, all of which may ultimately give rise to local relapse or overt metastasis. Initial studies simply recorded the presence and number of CTCs and DTCs; however recent advances are allowing assessment of the relationship between their persistence, patient prognosis and the biological properties of MRD, leading to a better understanding of the metastatic process. Technological developments for the isolation and analysis of circulating and disseminated tumour cells continue to emerge, creating new opportunities to monitor disease progression and perhaps alter disease outcome. This review outlines our knowledge to date on both measurement and categorisation of MRD in the form of CTCs and DTCs with respect to how this relates to cancer outcomes, and the hurdles and future of research into both CTCs and DTCs.

Does primary neoadjuvant systemic therapy eradicate minimal residual disease? Analysis of disseminated and circulating tumor cells before and after therapy

BACKGROUND

Patients with breast cancer (BC) undergoing neoadjuvant chemotherapy (NACT) may experience metastatic relapse despite achieving a pathologic complete response. We analyzed patients with BC before and after NACT for disseminated tumor cells (DTCs) in the bone marrow(BM); comprehensively characterized circulating tumor cells (CTCs), including stem cell-like CTCs (slCTCs), in blood to prove the effectiveness of treatment on these cells; and correlated these findings with response to therapy, progression-free survival (PFS), and overall survival (OS).

METHODS

CTCs (n = 135) and slCTCs (n = 91) before and after NACT were analyzed using the AdnaTest BreastCancer, AdnaTest TumorStemCell, and epithelial-mesenchymal transition (QIAGEN Hannover GmbH Germany). The expression of estrogen receptor, progesterone receptor, and the resistance marker excision repair cross-complementing rodent repair deficiency, complementation group 1 (ERCC1), nuclease were studied in separate single-plex reverse transcription polymerase chain reaction experiments. DTCs were evaluated in 142 patients before and 165 patients after NACT using the pan-cytokeratin antibody A45-B/B3 for immunocytochemistry.

RESULTS

The positivity rates for DTCs, CTCs, and slCTCs were 27 %, 24 %, and 51 % before and 20 %, 8 %, and 20 % after NACT, respectively. Interestingly, 72 % of CTCs present after therapy were positive for ERCC1, and CTCs before (p = 0.005) and after NACT (p = 0.05) were significantly associated with the presence of slCTCs. Whereas no significant associations with clinical parameters were found for CTCs and slCTCs, DTCs were significantly associated with nodal status (p = 0.03) and histology (0.046) before NACT and with the immunohistochemical subtype (p = 0.02) after NACT. Univariable Cox regression analysis revealed that age (p = 0.0065), tumor size before NACT (p = 0.0473), nodal status after NACT (p = 0.0137), and response to NACT (p = 0.0136) were significantly correlated with PFS, whereas age (p = 0.0162) and nodal status after NACT (p = 0.0243) were significantly associated with OS. No significant correlations were found for DTCs or any CTCs before and after therapy with regard to PFS and OS.

CONCLUSIONS

Although CTCs were eradicated more effectively than DTCs, CTCs detected after treatment seemed to be associated with tumor cells showing tumor stem cell characteristics as well as with resistant tumor cell populations that might indicate a worse outcome in the future. Thus, these patients might benefit from additional second-line treatment protocols including bisphosphonates for the eradication of DTCs.

Circulating Tumor Cell Analyses in Patients With Esophageal Squamous Cell Carcinoma Using Epithelial Marker-Dependent and -Independent Approaches

In several epithelial malignancies, detection of circulating tumor cells (CTCs) in the peripheral blood has diagnostic, prognostic, and therapeutic implications. However, the clinical relevance of CTCs in esophageal squamous cell carcinoma (ESCC) has not yet been ascertained. The study was conducted with the aim of determining the clinical significance of CTCs in patients with ESCC by using 2 CTC detection systems, one epithelial marker-dependent and the other epithelial marker-independent. Paired peripheral blood samples were prospectively obtained from 61 ESCC patients before treatment and were analyzed for CTCs isolated by the CellSearch system (CS) and the method of isolation by size of epithelial tumor (ISET). Blood samples from 22 healthy volunteers were used as controls. Out of 61 study subjects, CTCs were detected in 20 patients (32.8%) by the ISET method and in only 1 patient (1.6%) by the CS method. Circulating tumor microemboli (CTM) were observed in 3 of 61 (4.9%) patients using ISET, but were undetectable in any of the patient by CS method. No CTCs/CTM were detected by either method in control groups. By ISET method, the presence of CTCs appeared to correlate with the stage of ESCC and with the baseline median platelet levels. No correlation with any other relevant clinicopathological variables was observed. Our results clearly indicate the ability of both CS and ISET methods to detect CTCs in peripheral blood samples from ESCC patients. However, the CellSearch system appears to have a poorer sensitivity as compared with the ISET method. Further studies are essential for assessing the role of such technologies in ESCC.

Loss of the obscurin-RhoGEF downregulates RhoA signaling and increases microtentacle formation and attachment of breast epithelial cells

Obscurins are RhoGEF-containing proteins whose downregulation has been implicated in the development and progression of breast cancer. Herein, we aim to elucidate the mechanism for increased motility of obscurin-deficient cells. We show that shRNA-mediated obscurin downregulation in MCF10A cells leads to >50% reduction in RhoA activity relative to scramble control (shCtrl), as well as decreased phosphorylation of RhoA effectors, including myosin light chain phosphatase, myosin light chain, lim kinase, and cofilin, in both attached and suspended cells. These alterations result in decreased actomyosin contractility, allowing suspended cells to escape detachment-induced apoptosis. Moreover, ~40% of shObsc-expressing cells, but only ~10% of shCtrl-expressing cells, extend microtentacles, tubulin-based projections that mediate the attachment of circulating tumor cells to endothelium. Indeed, we show that MCF10A cells expressing shObsc attach in vitro more readily than shCtrl cells, an advantage that persists following taxane exposure. Overall, our data suggest that loss of obscurins may represent a substantial selective advantage for breast epithelial cells during metastasis, and that treatment with paclitaxel may exacerbate this advantage by preferentially allowing obscurin-deficient, stem-like cells to attach to the endothelium of distant sites, a first step towards colonizing metastatic tumors.

Gene profiling and circulating tumor cells as biomarker to prognostic of patients with locoregional breast cancer

The gene profile of primary tumors, as well as the identification of circulating tumor cells (CTCs), can provide important prognostic and predictive information. In this study, our objective was to perform tumor gene profiling (TGP) in combination with CTC characterization in women with nonmetastatic breast cancer. Biological samples (from peripheral blood and tumors) from 167 patients diagnosed with stage I, II, and III mammary carcinoma, who were also referred for adjuvant/neoadjuvant chemotherapy, were assessed for the following parameters: (a) the presence of CTCs identified by the expression of CK-19 and c-erbB-2 in the peripheral blood mononuclear cell (PBMC) fraction by quantitative reverse transcription PCR (RT-PCR) and (b) the TGP, which was determined by analyzing the expression of 21 genes in paraffin-embedded tissue samples by quantitative multiplex RT-PCR with the Plexor® system. We observed a statistically significant correlation between the progression-free interval (PFI) and the clinical stage (p = 0.000701), the TGP score (p = 0.006538), and the presence of hormone receptors in the tumor (p = 0.0432). We observed no correlation between the PFI and the presence or absence of CK-19 or HER2 expression in the PBMC fraction prior to the start of treatment or in the two following readouts. Multivariate analysis revealed that only the TGP score significantly correlated with the PFI (p = 0.029247). The TGP is an important prognostic variable for patients with locoregional breast cancer. The presence of CTCs adds no prognostic value to the information already provided by the TGP.

Current and potential use of MAINTRAC method for cancer diagnosis and prediction of metastasis

Cells shed from solid malignant tumors into the circulation are considered to be the origin of metastases. In spite of a wealth of research on the pathway of metastasis formation, it is still not clear when and how metastases develop, nor is there a consensus on the number and the nature of circulating tumor cells present in individual patients and their relationship to the formation of metastases. We have developed a method to detect a maximum of unselected non-hematological, epithelial cells in the blood, assuming that in cancer patients the majority of these cells are derived from the tumor. Assessment of the number of these cells longitudinally during the course of disease and therapy allows the response to different treatments to be monitored. Due to the viability of the cells, additional analyses such as expression profiles and determination of their sensitivity to drugs can be performed.

May CTC technologies promote better cancer management?

In the case of cancer, death is usually not due to the primary tumor itself but due to dissemination. Analysis of the circulating tumor cells (CTCs), i.e., cells responsible for a formation of metastases, should provide information useful for the management of cancer patients, fulfilling the objectives of predictive, preventive, and personalized medicine (PPPM). Despite promising results, the decisions on stage of disease and how to guide the adjuvant treatment still do not include results of CTC assessment. We want to describe two major reasons why the recent diagnostic value of CTC analysis is not sufficient for clinical use. The first reason arises from the biological nature of the tumor itself and the second reason is associated with an interdisciplinary status of CTC diagnostics in the sense that it is neither a theme purely for pathologists nor for haemato-oncologists nor clinical biochemists. We anticipate that there are at least three areas where CTCs can be useful for clinical practice. The first is monitoring of treatment efficacy of cancer patients. The second is a molecular characterization of captured CTCs for targeted treatment, and the third is a cultivation of captured CTCs for drug sensitivity testing. All of these approaches allow researchers recognize and respond to changes of phenotype of cancer cells during disease progression and introduce PPPM into clinical practice.

Novel tools for prostate cancer prognosis, diagnosis, and follow-up

Prostate-specific antigen (PSA) is the main diagnostic tool when it comes to prostate cancer but it possesses serious limitations. Therefore, there is an urgent need for more sensitive and specific biomarkers for prostate cancer prognosis and patient follow-up. Recent advances led to the discovery of many novel diagnostic/prognostic techniques and provided us with many worthwhile candidates. This paper briefly reviews the most promising biomarkers with respect to their implementation in screening, early detection, diagnostic confirmation, prognosis, and prediction of therapeutic response or monitoring disease and recurrence; and their use as possible therapeutic targets. This review also examines the possible future directions in the field of prostate cancer marker research.

Are changes in circulating tumor cell (CTC) count associated with the response to neoadjuvant chemotherapy in local advanced breast cancer? A meta-analysis

INTRODUCTION

Circulating tumor cells (CTCs) represent a biomarker for tumor progression and monitoring therapeutic effects. We evaluated the association between the changes in CTC count and the pathological response to neoadjuvant chemotherapy (NCT) for local advanced breast cancer (LABC) patients.

METHODS

PubMed, EBSCO, Web of Science, conference proceedings and key trials for the period 1998-2012 were searched. We used the hazard ratio (HR) to evaluate the variation in the number of CTCs to predict the response to NCT in LABC patients. All data from each study were investigated using either fixed- or random-effect models and were analyzed using Stata software.

RESULTS

There was no between-study heterogeneity in pathological complete response (pCR) (heterogeneity chi-squared = 0.02 (df = 1), I(2) = 0.0%, p = 0.877). Our meta-analysis showed that the change (decrease or increase) in CTC number in LABC patients during NCT was not correlated with pCR (HR = 0.918, 95% confidence interval 0.650-1.295; p = 0.877).

CONCLUSION

The results of the current meta-analysis indicate that there is no association between the decrease of CTC number and pCR after NCT. According to our results, a decrease in the CTC count after NCT in LABC patients did not indicate that they had an improved response to NCT. However, more randomized clinical trials are needed to confirm this conclusion.

Analysis of circulating tumor cells in breast cancer

Over the past few decades, substantial progress has been made in the diagnosis and treatment of breast cancer. Early identification of relapsed and metastatic disease has been a primary focus of ongoing research. Circulating tumor cells (CTCs) are implicated as harbingers of metastases. With advances in detection technologies, CTCs offer the option for real-time liquid biopsies. Methods to identify CTCs in the bloodstream by physical or biochemical properties, although feasible, still require improvements to promote widespread, reproducible use. Sufficient data support enumeration and assessment of changes in the number of CTCs as prognostic indicators, but controversy around their predictive utility for selecting treatments remains. As the technology to detect CTCs and characterize their heterogeneous molecular profile evolves, additional information will likely be obtained to guide targeted and individualized therapies.

Heterogeneity of circulating epithelial tumour cells from individual patients with respect to expression profiles and clonal growth (sphere formation) in breast cancer

Background

The detection of tumour cells circulating in the peripheral blood of patients with breast cancer is a sign that cells have been able to leave the primary tumour and survive in the circulation. However, in order to form metastases, they require additional properties such as the ability to adhere, self-renew, and grow. Here we present data that a variable fraction among the circulating tumour cells detected by the Maintrac^® approach expresses mRNA of the stem cell gene NANOG and of the adhesion molecule vimentin and is capable of forming tumour spheres, a property ascribed to tumour-initiating cells (TICs).

Patients and methods

Between ten and 50 circulating epithelial antigen-positive cells detected by the Maintrac approach were selected randomly from each of 20 patients with breast cancer before and after surgery and were isolated using automated capillary aspiration and deposited individually onto slides for expression profiling. In addition, the circulating tumour cells were cultured without isolation among the white blood cells from 39 patients with breast cancer in different stages of disease using culture methods favouring growth of epithelial cells.

Results

Although no epithelial cell adhesion molecule (EpCAM)-positive cells expressing stem cell genes or the adhesion molecule vimentin was detected before surgery, 10%–20% of the cells were found to be positive for mRNA of these genes after surgery.

Tumour spheres from circulating cells of 39 patients with different stages of breast cancer were grown without previous isolation in a fraction increasing with the aggressivity of the tumour.

Summary

Here we show that among the peripherally circulating tumour cells, a variable fraction is able to express stem cell and adhesion properties and can be grown into tumour spheres, a property ascribed to cells capable of initiating tumours and metastases.

Differential effect of adjuvant taxane-based and taxane-free chemotherapy regimens on the CK-19 mRNA-positive circulating tumour cells in patients with early breast cancer

Background:

To determine the effect of adjuvant taxane-free and taxane-based chemotherapy regimens on the elimination of circulating tumour cells (CTCs) in patients with early breast cancer.

Methods:

The presence of CK-19 mRNA-positive CTCs in the peripheral blood was evaluated before and after chemotherapy, using a real-time RT–PCR assay, in a historical comparison of two cohorts of women with stage I–III breast cancer treated with adjuvant taxane-free (N=211; FE₇₅C or E₇₅C) and taxane-based (N=334; T/E₇₅C or T/E₇₅) chemotherapy.

Results:

Taxane-based chemotherapy resulted in a higher incidence of CTCs' elimination than taxane-free regimens since 49.7% (74 of 149) and 33.0% (29 of 88) of patients with detectable CTCs before chemotherapy, respectively, turned negative post-chemotherapy (P=0.015). Patients treated with taxane-free regimens had a significantly lower disease-free survival (DFS) (P=0.035) than patients treated with taxane-based regimens; this difference was observed in patients with but not without detectable CTCs before chemotherapy (P=0.018 and P=0.481, respectively). The incidence of deaths was significantly higher in the taxane-free cohort of patients with but not without detectable CTCs before chemotherapy compared with that of the taxane-based cohort (P=0.002). Multivariate analysis revealed that the chemotherapy regimen was significantly associated with prolonged DFS (HR: 2.00; 95% CI=1.20–3.34).

Conclusion:

Elimination of CK-19 mRNA-positive CTCs during adjuvant chemotherapy seems to be an efficacy indicator of treatment and is associated with a favourable clinical outcome of patients with detectable CTCs before chemotherapy.

The presence and prognostic impact of apoptotic and nonapoptotic disseminated tumor cells in the bone marrow of primary breast cancer patients after neoadjuvant chemotherapy

INTRODUCTION

Neoadjuvant systemic therapy of primary breast cancer (PBC) patients offers the possibility to monitor treatment response. However, patients might have metastatic relapse despite achieving a pathologic complete response (pCR). This indicates that local response to therapy must not be representative for systemic treatment efficacy. Therefore, the aim of this study was to compare local response with systemic tumor cell dissemination by determining the presence of disseminated tumor cells (DTCs), including apoptotic tumor cells, in the bone marrow (BM) of PBC patients after neoadjuvant chemotherapy (NACT).

METHODS

DTCs were detected by immunocytochemistry (pancytokeratin antibody A45-B/B3) and cytomorphology (DTC status). The presence of apoptotic tumor cells was determined by using the M30 antibody (M30 status). This antibody detects a neo-epitope that is expressed only during early apoptosis.

RESULTS

BM aspirates from 400 PBC patients that had completed NACT were eligible for this study. Of these, 167 (42%) patients were DTC positive (DTC status). The M30 status was investigated in 308 patients. Apoptotic (M30-positive) tumor cells were detected in 89 (29%) of these. Whereas the DTC status was not correlated (P = 0.557) to local treatment response (that is, pCR or a clinical complete/partial response), the presence of M30-positive tumor cells was significantly higher in patients that responded to therapy (P = 0.026). Additionally, DTC-positive patients were at an increased risk for disease relapse (hazard ratio, 1.87; 95% CI, 1.11 to 3.15; P = 0.019).

CONCLUSION

The presence of DTC is independent of therapy response of the primary tumor. As patients that are DTC positive after NACT have an unfavorable outcome, they might benefit from additional systemic treatment.

Serum DNA methylation for monitoring response to neoadjuvant chemotherapy in breast cancer patients

Patients with large or nonoperable breast cancers often receive neoadjuvant chemotherapy to facilitate full resection of the tumor and enable conservation of the breast. However, currently available methods for evaluation of response during therapy are limited and the actual effect of the treatment is only recognized at surgery upon completion of chemotherapy. Timely assessment of response could allow individual tailoring of the treatment and save noneffective drugs and unnecessary toxicity. Here, we suggest that tumor derived DNA methylation in the serum may reflect changes in tumor burden and allow early recognition of responders versus nonresponders. In this pilot study, we collected 7 consecutive serum samples from 52 patients with locally advanced breast cancer during neoadjuvant chemotherapy. We selected RASSF1, which was methylated in more than 80% of the tumors, for serum analysis. Using the "methylation sensitive PCR and high resolution melting," we detected RASSF1 methylation in the serum of 21 patients prior to therapy. In four patients who achieved complete pathological response, RASSF1 methylation in the serum became undetectable early during therapy. In contrast, in 17 patients that had partial or minimal pathological response, serum RASSF1 methylation persisted longer or throughout the treatment (complete versus partial response p = 0.02). These findings support further development of this assay for monitoring response during neoadjuvant therapy.

Epithelial cell dissemination and readhesion: analysis of factors contributing to metastasis formation in breast cancer

Although considerable progress has been achieved in breast cancer diagnosis and treatment, the live-saving effect of mammography has hardly been measurable and the benefit of taxanes regarded as highly active is still a matter of debate, possibly because treatment effects have hitherto been mainly determined from the solid part of the tumor, due to lack of measurability of the systemic part of the disease. Here, we have quantified the influence on the systemic disease, cells mobilized from the solid tumor. Increased numbers of circulating epithelial cells were observed in screened individuals and still higher numbers in breast cancer patients with repeated mammograms as compared to mammogram naïve individuals. Taxanes as part of the subsequent systemic treatment led to mobilization of tumor suspect cells in up to 78% cases and the majority of relapses have occurred in these patients. Surgery-induced activation of disseminated cells may additionally contribute to metastasis formation.

Circulating Tumor Cells in Early-Stage Breast Cancer

Disseminated tumor cells (DTC) are routinely detected in bone marrow (BM) in 30-40 % of primary breast cancer patients. Positive BM status at the time of diagnosis as well as DTC persistence after therapy are strong independent prognostic factors. Since repeated BM aspirations are not well tolerated, detection of single tumor cells in peripheral blood (circulating tumor cells; CTC) have become of interest in recent years. CTC are found in 10-80 % breast cancer patients. Variability can be explained by stage of the disease and detection method. Emerging data have shown CTC to be of prognostic relevance for both, patients with primary and metastatic disease. The assessment of CTC in blood may become an important biomarker for prognostication and therapy monitoring. Determination of their molecular characteristics will enable specific targeting of minimal residual as well as metastatic disease. This review summarizes recent research and future perspectives.

True local recurrences do not metastasize

Generally, the limits of local tumor control are in part connected with the term "field cancerization" and are known from oral, lung, prostate, or mammary cancer. With the example of breast cancer (BC), the problem of ipsilateral breast tumor recurrences (IBTR) after breast-conserving surgery will be reviewed. Three types of local recurrences are distinguished: true recurrences, new primaries, or residual tumors. Good data for BC allow the description of the time-dependent risk of these three types, relative to the diagnosis of the primary tumor, because the time of initiation and the growth duration of the IBTR can be estimated. Two hypotheses explain the data: first, local recurrences may be initiated years before the diagnosis of a primary tumor (PT) and can then appear as multifocal PT at diagnosis, and second, true local recurrences probably do not metastasize. The generalizability of these hypotheses for other tumors will be discussed.