Correlation between genetic and biological aspects in primary non-metastatic breast cancers and corresponding synchronous axillary lymph node metastasis

Clinical relevance of biomarker discordance between primary breast cancers and synchronous axillary lymph node metastases

Clinical decision-making for patients with breast cancer (BC) is still primarily based on biomarker characteristics of the primary tumor, together with the evaluation of synchronous axillary lymph node metastasis (LNM). In this study, we investigated the prevalence of discordance in the biomarkers and surrogate subtyping between the primary BC and the LNM, and whether subsequent changes would have altered clinical treatment recommendations. In this retrospective study, 94 patients treated for unifocal primary BC and synchronous LNM at Sahlgrenska UniversityHospital during 2018 were included. Estrogen (ER) and progesterone (PR) receptor, Ki67, and HER2 status were assessed in the primary tumor and LNM using immunohistochemistry. Discordances between the primary tumor and the LNM were analyzed for each individual biomarker and surrogate subtyping. The concordance between the primary tumor and the LNM for ER, PR, Ki67, and HER2 status was 98.9%, 89.4%, 72.3%, and 95.8%, respectively. Discordance in surrogate subtyping was found in 28.7% of the tumors and matched LNMs, the majority (81.5%) of which changed to a more favorable subtype in the LNM; most commonly from Luminal B to Luminal A (48.6%). No changes in surrogate subtyping were detected where ER or HER2 status changed from negativity in the BC to positivity in the LNM, thereby showing no additional value in performing immunohistochemistry on the LNM from a treatment decision-making perspective. However, large studies need to be performed that test both the primary BCs and synchronous LNMs for more accurate diagnostics.

Heterogeneity between Core Needle Biopsy and Synchronous Axillary Lymph Node Metastases in Early Breast Cancer Patients-A Comparison of HER2, Estrogen and Progesterone Receptor Expression Profiles during Primary Treatment Regime

Simple Summary

All initial therapeutic decisions in early breast cancer are commonly based on the intrinsic subtype consisting of estrogen (ER), progesterone (PR), the human epidermal growth factor 2 (HER2) receptors and the proliferation marker Ki67. However, breast cancer is a very heterogeneous disease, and receptor expression is reported to change during progression. Little is known about receptor changes at the primary site. In a German single center study, we retrospectively analyzed a mostly therapy naive cohort of 215 primary breast cancer patients with axillary synchronous lymph node metastases (LNM). We compared core needle biopsy tissue of the primary tumor (t-CNB) to axillary LNM and detected receptor discordance for all three receptors at the primary site.

Abstract

In breast cancer therapeutic decisions are based on the expression of estrogen (ER), progesterone (PR), the human epidermal growth factor 2 (HER2) receptors and the proliferation marker Ki67. However, only little is known concerning heterogeneity between the primary tumor and axillary lymph node metastases (LNM) in the primary site. We retrospectively analyzed receptor profiles of 215 early breast cancer patients with axillary synchronous LNM. Of our cohort, 69% were therapy naive and did not receive neoadjuvant treatment. Using immunohistochemistry, receptor status and Ki67 were compared between core needle biopsy of the tumor (t-CNB) and axillary LNM obtained during surgery. The discordance rates between t-CNB and axillary LNM were 12% for HER2, 6% for ER and 20% for PR. Receptor discordance appears to already occur at the primary site. Receptor losses might play a role concerning overtreatment concomitant with adverse drug effects, while receptor gains might be an option for additional targeted or endocrine therapy. Hence, not only receptor profiles of the tumor tissue but also of the synchronous axillary LNM should be considered in the choice of treatment.

Intertumoral Heterogeneity of Primary Breast Tumors and Synchronous Axillary Lymph Node Metastases Reflected in IHC-Assessed Expression of Routine and Nonstandard Biomarkers

Breast cancer (BC) remains a significant healthcare challenge. Routinely, the treatment strategy is determined by immunohistochemistry (IHC)-based assessment of the key proteins such as estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67. However, it is estimated that over 75% of deaths result from metastatic tumors, indicating a need to develop more accurate protocols for intertumoral heterogeneity assessment and their consequences on prognosis. Therefore, the aim of this preliminary study was the identification of the expression profiles of routinely used biomarkers (ER, PR, HER2, Ki-67) and additional relevant proteins [Bcl-2, cyclin D1, E-cadherin, Snail+Slug, gross cystic disease fluid protein 15 (GCDFP-15), programmed death receptor 1 (PD-L1), and phosphatase of regenerating liver 3 (PRL-3)] in breast primary tumors (PTs) and paired synchronous axillary lymph node (ALN) metastases. A total of 67 tissue samples met the inclusion criteria for the study. The expression status of biomarkers was assessed in PTs and ALN metastases using tissue microarrays followed by IHC. In 11 cases, the shift of intrinsic molecular BC subtype was noticed between PTs and paired ALN metastases. Moreover, a significant disproportion in E-cadherin presence (p = 0.0002) was noted in both foci, and the expression status of all proteins except for HER2 demonstrated considerable variance (k = 1, p < 0.0001). Importantly, in around 30% of cases, the ALN metastases demonstrated discordance, i.e., loss/gain of expression, compared to the PTs. Intertumoral synchronous heterogeneity in both foci (primary tumor and node metastasis) is an essential phenomenon affecting the clinical subtype and characteristics of BC. Furthermore, a greater understanding of this event could potentially improve therapeutic efficacy.

Biomarker heterogeneity between primary breast cancer and synchronous axillary lymph node metastases

Whether the expression status of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2) receptor and Ki-67 show concordance between the primary tumors and the synchronous axillary lymph node (ALN) metastases has been discussed in numerous studies. However, to date, the results of these studies remain controversial. Therefore, the present study aimed to investigate whether the expression of ER, PR, HER-2 and Ki-67 was in concordance between the primary tumors and synchronous ALN metastases in patients with operable breast cancer (BC). A total of 60 tissue samples were collected from patients with primary operable BC diagnosed with primary tumors and synchronous ALN metastases. The expression levels of the four biomarkers, ER, PR, HER-2 and Ki-67, were assessed in primary lesions and synchronous ALN metastases samples using immunohistochemistry. The cut-off values were set to 10% for ER and PR, while the labeling index of Ki-67 was set to 14%. The immunostaining intensity of ER and PR was scored as negative (−), 1+, 2+ and 3+. The criteria for HER-2 testing in BC were implemented according to the American Society of Clinical Oncology (ASCO) and the College of American Pathologists (CAP) guidelines. The concordance rates for ER, PR and HER-2 were 96.7 (58/60), 96.7 (58/60) and 90% (54/60), respectively. In addition, the kappa values of consistency in the primary lesions and the synchronous ALN metastases were 0.773 for ER, 0.654 for PR and 0.785 for HER-2. Furthermore, the P-values of ER, PR and Ki-67 numerical variables between the two groups were 0.393, 0.400 and 0.331, respectively, as demonstrated using a non-parametric Wilcoxon signed rank test. The findings of the present study demonstrated a high degree of concordance between the expression of ER, PR, HER-2 and Ki-67 in the primary tumors and that in the synchronous ALN metastases, suggesting that the BC primary tumor biomarkers may be used for the prognosis of synchronous ALN metastases in patients with operable BC.

Expression Patterns of Biomarkers in Primary Tumors and Corresponding Metastases in Breast Cancer

Tumor heterogeneity has been shown for several cancers including breast cancer (BC). Despite the fact that expression of tumor markers may change throughout the metastatic process, rebiopsies at the time of recurrence are still not performed routinely at all institutions. The aims of the study were to evaluate changes in biomarker profiles during the metastatic process and to investigate whether previous anthracycline or endocrine therapy given in the adjuvant setting could affect the biomarker profile in metastatic lesions. We investigated the expression pattern of ER, HER2, TOP2a, TOP1, p53, Bcl-2, and Ki-67 in 110 paired samples of primary BC and corresponding asynchronous metastases. We found discordant expressions in primary tumor and metastasis for all biomarkers, although only significant for Ki-67. Changes in the expression profile of the metastatic lesions would have altered treatment decisions in 14% of patients. We found no effect of previous anthracycline or endocrine therapy on the expression profiles. Our data confirm that discordant expressions of biomarkers are common in BC and often carry therapeutic consequences. This emphasizes the need for biopsies from metastatic lesions, even in cases where the localization of the metastatic process is not easily accessible.

HER-2/Neu and Hormone Receptor Analysis in Breast Carcinomas and Their Association with Clinicopathologic Parameters

Objective

Invasive breast carcinomas of no special type (IC-NST) are the heterogeneous tumours showing distinct prognostic features even in patients with similar clinicopathological characteristics. To date, many clinicopathological data have been analyzed to make a guess about prognosis and to determine treatment modality. In this study, HER-2/neu status was analyzed by using both immunohistochemical (IHC) and fluorescence in situ hybridization (FISH) methods, and its correlations with hormone receptor status and clinicopathological parameters were investigated.

Materials and Methods

The study was included 112 female patients with diagnosis of IC-NST. FISH for HER-2/neu was applied in only primary tumour tissues, while IHC analyses for HER-2/neu, estrogen (ER) and progesterone receptors (PR) were applied on both primary and metastatic lymph node foci. The results were compared with appropriate statistical methods.

Results

Our rates of HER-2/neu overexpression and gene amplification in the overall study group were 22.3 and 25%, respectively. In the metastatic group, these rates were higher than those of the overall study group (34% and 40%, respectively). Gene amplification rate of the axilla positive group was 40%, while this rate in non-metastatic group was 6.7% (p=0.015). Overexpression and amplification results were compliant (χ²=77,591, p<0.001). The concordance rates in HER-2/neu negative and overexpression groups were 95.3% and 88%, respectively. Our false negativity rate was 4.7%. While 36% of score 3+ cases were ER positive, 67.1% of HER-2/neu negative cases showed ER positivity (p=0.01). The increase of gene amplification rate in ER negative cases over 50 years age was more than two times and statistically significant (p=0.014).

Conclusion

The concordance rates between the results of IHC and FISH in the HER-2 negative and the overexpression categories were compatible with the literature and lower than the literature, respectively. In the case of ER negativity, the patient's age over 50 years was associated with a higher rate of gene amplification.

Occult breast cancer may originate from ectopic breast tissue present in axillary lymph nodes

PURPOSE

Occult breast cancer (OBC) is classified as a carcinoma of unknown primary, and involves axillary lymphadenopathy and is histologically consistent with metastatic breast cancer. OBC has been conventionally considered as a metastatic lymph node lesion, the origin of which is an undetectable breast tumor. Therefore, OBC patients would usually have undergone axillary lymph node dissection, and mastectomy or whole breast radiotherapy (WBRT). However, majority of OBC reports have been based on cases that were diagnosed during a period when diagnostics was still relatively primitive, and when magnetic resonance imaging was not yet a standard preoperative assessment. Therefore, there have been many false negatives in the breast based on preoperative assessment.

METHODS

We herein hypothesize that the origin of OBC is ectopic breast tissue present in axillary lymph nodes (ALNs). If our hypothesis is true, mastectomy and WBRT may be unnecessary for OBC patients.

RESULTS

Our hypothesis is supported by several findings. First, advances in radiological imaging have suggested that a primary breast tumor is absent in OBC patients. Second, proliferative breast lesions arising from ectopic breast present in ALNs have been reported. Lastly, cellular subtypes in OBC based on immunohistochemistry are of various types including ordinary breast cancer and the prognosis is not worse than stage II breast cancer.

CONCLUSION

It is important to distinguish between "primary" OBC in ALNs and "metastatic" OBC from micro-primary breast tumor. Further studies are required to determine if omission of mastectomy and WBRT is acceptable.

The Future of Anti-EGFR Therapy

We report here on the state of our knowledge of the target - namely, the epidermal growth factor (EGF) and its receptor - and the challenges related to the methods of determination of the epidermal growth factor receptor (EGFR) and associated molecular pathways. A critical review of the anti-EGFR therapeutic strategies is also outlined. The chimeric anti-EGFR monoclonal antibody cetuximab has been approved for EGFR-expressing colorectal tumors in patients who progress after irinotecan-based chemotherapy in combination with irinotecan and in squamous cell head and neck carcinomas for patients with locally advanced disease in combination with radiation therapy or after failure of platinum-based chemotherapy in recurrent or metastatic disease (FDA). Cetuximab has the potential to provide an improvement of clinical outcome also in other indications and tumor types, particularly when used as first-line therapy combined with standard chemotherapy for metastatic disease or in the adjuvant setting. Possible strategies to improve the effectiveness of anti-EGFR agents are suggested and include (i) the use of predictive tools capable of making a more rational selection of patients; (ii) the development of standardized predictive biomarkers as surrogates for early monitoring of drug efficacy; and (iii) adequate study design, statistical analysis and proper end points of efficacy to be applied in future prospective trials.

Clinical Significance of Subtype Classification in Metastatic Lymph Nodes of Breast Cancer Patients Undergoing Neoadjuvant Chemotherapy

Background

Neoadjuvant chemotherapy has been increasingly utilized in the treatment of breast cancer patients. However, there are no established surrogate markers predicting the response to subsequent adjuvant therapy and clinical outcome of patients. In particular, whether primary or lymph nodes metastasis should be evaluated for these analyses has remained unknown. Therefore, in this study, we first evaluated the differences in biomarkers between primary and metastatic cancer tissues in the patients undergoing neoadjuvant chemotherapy. We then correlated the findings with the clinical outcomes of these patients.

Methods

We examined 49 patients receiving neoadjuvant chemotherapy and subsequent surgery with lymph node metastasis. Estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor 2 (HER2) and Ki-67 were all immunohistochemically evaluated in core needle biopsy samples from primary and metastatic tumors following chemotherapy.

Results

No statistically significant differences in these markers were detected between the primary tumor and metastatic lymph nodes following therapy, but the Ki-67 labeling index was significantly higher in metastatic lymph nodes than in primary tumor (p = 0.017). The patients associated with luminal A type carcinoma in their lymph nodes following chemotherapy demonstrated significantly better clinical outcomes (disease-free survival: p = 0.0045, overall survival: p = 0.0006) than those who were not.

Conclusion

These data indicate that subtype classification following chemotherapy, in the metastatic lymph nodes rather than primary tumor could predict long-term outcomes of patients undergoing neoadjuvant chemotherapy.

Breast Carcinoma-associated Fibroblasts Share Similar Biomarker Profiles in Matched Lymph Node Metastasis

This study sought to understand the role of breast carcinoma-associated fibroblasts in the progression of cancer cells into lymph nodes. We compared fibroblasts of primary tumors and matched the involved lymph nodes to select fibroblast activation markers, namely α-smooth muscle actin (α-SMA), S100A4, and vimentin, as well as to determine the frequency of transforming growth factor β1, a pleiotropic cytokine that induces the differentiation of fibroblasts to myofibroblasts, and its downstream effectors: CXCR4 and p-AKT. We disposed samples of 80 primary invasive ductal carcinomas and matched the involved lymph nodes from 43 cases into 3 tissue microarrays, and analyzed stromal and tumor epithelial cells separately by immunohistochemistry. Control uninvolved lymph nodes were analyzed by whole-tissue sections. Cancer-associated fibroblast in lymph nodes with macrometastasis expressed similar profiles of vimentin, α-SMA, and S100A4 as those found in primary tumors. Cancer-associated fibroblast were uniformly estrogen receptor, progesterone receptor, HER-2, Ki-67, and p53 negative, but expressions of transforming growth factor β1 (TGFβ1), CXCR4, and p-AKT staining (62.3%, 52.4%, 65%, respectively) were equivalent between primary and lymph node metastasis (LNM) fibroblasts. A significant coexpression of TGFβ1 with p-AKT and CXCR4 in LNMs suggested the involvement of these proteins with TGFβ1 signaling. These biomarkers, including α-SMA and S100A4, were negative in fibroblasts of cancer-free lymph nodes, with the exception of vimentin. Our finding that expressions of biological markers were similar in fibroblasts of the primary tumors and in matched LNMs, but were absent in cancer-free lymph nodes, supports the assumption that the lymph node stroma mimics the microenvironment observed in primary tumors.

P-cadherin: a useful biomarker for axillary-based breast cancer decisions in the clinical practice

Axillary lymph node metastases represent the most powerful breast cancer prognostic factor, dictating disease staging and clinical therapeutic decisions. Nonetheless, breast cancer patients with positive lymph nodes still exhibit a heterogeneous behavior regarding disease progression. Stem-like subpopulations of cancer cells show high migratory and metastatic capacity, thus we hypothesize that breast cancer stem cell markers evaluation in metastasized lymph nodes could provide a more accurate prediction of patient's prognosis. Therefore, the expression profile of P-cadherin, CD44, and CD49f, which have been already associated to stem cell properties in breast cancer, has been evaluated by immunohistochemistry in a series of 135 primary tumors and matched axillary lymph node metastases from 135 breast cancer patients. Taking in consideration the expression of the stem cell markers only in axillary nodes, P-cadherin was the only biomarker significantly associated with poor disease-free and overall patient's survival. Moreover, although a concordant expression between primary tumors and matched lymph nodes has been found in the majority of the cases, a small but significant percentage displayed divergent expression (18.2-26.2%). Remarkably, although CD44 and CD49f changes between primary tumors and lymph node metastasis did not impact survival, the cases that were positive for P-cadherin in lymph node metastases being negative in the primary tumor, presented the worst disease-free and overall survival of the whole series. Accordingly, negative cases for this marker in the lymph nodes with positive expression in the matched breast carcinoma demonstrated a better prognosis, which overlapped with tumors that were negative in both sites. P-cadherin and CD49f gain of expression was mainly found in triple-negative carcinomas. Our results indicate for the first time that the evaluation of P-cadherin expression in lymph node metastases is an important predictor of disease outcome, being a putative valuable marker for axillary-based breast cancer decisions in the clinical practice.

Estrogen, progesterone, and HER2/neu receptor discordance between primary and metastatic breast tumours-a review

Discordance in estrogen (ER), progesterone (PR), and HER2/neu status between primary breast tumours and metastatic disease is well recognized. In this review, we highlight how receptor discordance between primary tumours and paired metastasis can help elucidate the mechanism of metastasis but can also effect patient management and the design of future trials. Discordance rates and ranges were available from 47 studies (3384 matched primary and metastatic pairs) reporting ER, PR, and HER2/neu expression for both primary and metastatic sites. Median discordance rates for ER, PR, and HER2/neu were 14 % (range 0-67 %, IQR 9-25 %), 21 % (range 0-62 %, IQR 15-41 %), and 10 % (range 0-44 %, IQR 4-17 %), respectively. Loss of receptor expression was more common (9.17 %) than gain (4.51 %). Discordance rates varied amongst site of metastasis with ER discordance being highest in bone metastases suggesting that discordance is a true biological phenomenon. Discordance rates vary for both the biomarker and the metastatic site. Loss of expression is more common than gain. This can affect patient management as it can lead to a reduction in both the efficacy and availability of potential therapeutic agents. Future studies are recommended to explore both the mechanisms of discordance as well as its impact on patient outcome and management.

Survival of breast cancer patients according to changes in expression of selected markers between primary tumor and lymph node metastases

BACKGROUND

The differences between primary and metastatic tumor cells might be important for treatment selection and prognostication.

MATERIALS & METHODS

Expression of ER, PR, HER2, CK5/6, EGFR, Ki-67, Ep-CAM, P-cadherin, CD24, CD44, ALDH was assessed immunohistochemically in primary tumor (T) and corresponding synchronous nodal metastases (LNM) in 156 invasive ductal breast cancer patients (T ≥1, N ≥1, M0).

RESULTS

Independent negative prognostic factors for disease-free survival were pN3, ALDH immunopositivity in LNM, nonluminal A subtype in LNM, reduction of Ep-CAM expression in LNM, lack of changes or enhancement of CK5/6 and ALDH expression in LNM.

DISCUSSION

Our results suggest that in some cases expression of markers in lymph node metastases might bring additional prognostic information to that obtained from primary tumor.

Improving systemic breast cancer therapy: time to look beyond the primary tumour?

AIM

Intra and inter tumour heterogeneity is a known feature in cancer because tumour cells undergo changes at genetic and epigenetic level as they spread from their primary tumour site. Adjuvant treatment protocols in breast cancer are currently based on the biological characteristics of the primary tumour, which in most cases has been removed surgically. Considering tumour heterogeneity in metastases we examined the present status of knowledge regarding measurable differences in tumour profiling between the primary breast tumour and its synchronous axillary lymph node metastases (ALNM) and if so whether adjuvant therapy directed towards the tumour characteristics of the ALNM instead of those of the primary tumour is more effective.

METHODS

We performed a literature search in Pubmed with the following MeSH headings: HUMAN and BREAST NEOPLASMS and RECEPTORS and ErbB-2.

RESULTS

A significant change in tumour features was seen in metachronous metastases. In contrast, a high concordance of biomarker expression was reported between a primary breast tumour and its synchronous ALNM.

CONCLUSION

Tumour heterogeneity is a challenge for targeted therapy. A poor response can be explained by the diversity of tumour cells. The biological profile of synchronous ALNM measured by oestrogen (ER), progesterone (PR) and her-2-neu receptor status does not differ from the primary breast tumour and is not predictive of the tumour profile in metachronous metastasis. New techniques, such as profiling of circulating tumour cells or tumour behaviour in xenografts, are promising in directing more effective adjuvant therapy.

Alterations in hormonal receptor expression and HER2 status between primary breast tumors and paired nodal metastases: discordance rates and prognosis

BACKGROUND

We aimed to evaluate the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression discordance in matched pairs of primary breast cancer and lymph node metastasis specimens and determine the effect of discordance on prognosis.

MATERIALS AND METHODS

Among all patients diagnosed with lymph node metastases from 2004 to 2007, primary tumors and paired lymph node metastases were resected from 209 patients. The status of ER, PR, and HER2 expression was analyzed immunohistochemically in 200, 194, and 193 patients, respectively. Discordance was correlated with prognosis.

RESULTS

Biomarker discordance between primary tumors and paired lymph node metastases was 25.0% (50/200) for ER status, 28.9% (56/194) for PR status, and 14.0% (27/193) for HER2 status. ER positivity was a significant independent predictor of improved survival when analyzed in primary tumors and lymph node metastases. Patients with PR-positive primary tumors and paired lymph node metastases displayed significantly enhanced survival compared to patients with PR-positive primary tumors and PR-negative lymph node metastases. Patients with ER- and PR-positive primary tumors and paired lymph node metastases who received endocrine therapy after surgery displayed significantly better survival than those not receiving endocrine therapy. Similalry treated patients with PR-negative primary tumors and PR-positive paired lymph node metastases also displayed better survival than those not receiving endocrine therapy.

CONCLUSIONS

Biomarker discordance was observed in matched pairs of primary tumors and lymph node metastases. Such cases displayed poor survival. Thus, it is important to reassess receptor biomarkers used for lymph node metastases.

Three Metachronous Cases of HER2-Positive Breast Cancer Accompanied with Thyroid Cancer

BACKGROUND

Breast carcinoma (BC) and papillary thyroid carcinoma (PTC) occur predominantly in women. Many studies have shown that PTC is common among women with BC. Collision metastases in lymph nodes do occur but are not common.

CASE REPORT

Here we report 3 metachronous cases of BC with PTC. PTC developed after BC in each case. Histology and immunohistochemistry revealed that HER2 status was positive in each BC, and in 1, concurrent metastases of BC and PTC were shown in a lymph node of the left cervical region.

CONCLUSION

From our results, we speculate that women with HER2-positive breast cancer may be at a higher risk for thyroid cancer than other cancers. Finding 2 distinct types of cancer metastasized to 1 lymph node in a patient may, therefore, warrant a high index of suspicion and the use of immunohistochemical stains to differentiate the types of collision tumors.

BGX-Ki-67 index as a supplementary marker to MIB-1 index, enabling more precise distinction between luminal A and B subtypes of breast carcinoma and eliminating the problem of membranous/cytoplasmic MIB-1 staining

OBJECTIVES

We compared clinical utility of MIB-1 and BGX-Ki-67 clones of anti-Ki-67 antibody in a group of 156 patients with invasive ductal breast cancer.

METHODS

MIB-1 labeling index (MIB-1LI) and BGX labeling index (BGXLI) were evaluated immunohistochemically both in primary tumors (T) and synchronous lymph node metastasis (LNM).

RESULTS

In addition to nuclear MIB-1 staining, in 23 of 145 and 19 of 144 T and LNM, respectively, membranous/cytoplasmic labeling was found. In these cases, BGX-Ki-67 showed exclusively nuclear labeling and presented significantly higher labeling index. High BGXLI(T) was a significant independent negative prognostic factor for disease-free survival. Moreover, based on BGXLI(T)/BGXLI(LNM), patients with high MIB-1LI(T) were stratified into low- and high-risk carriers.

CONCLUSIONS

In carcinomas with membranous/cytoplasmic MIB-1 staining, additional assessment of BGXLI is recommended. It may help in defining breast cancer subtype and in selection of individuals at risk who, despite appropriate therapy, would benefit from more frequent controls aimed at earlier implementation of second-line treatment.

A dual tyrosine kinase inhibitor lapatinib suppresses overexpression of matrix metallopeptidase 1 (MMP1) in endometrial cancer

Endometrial cancers have been recently molecularly characterized; amplifications of human epidermal growth factor receptor 2 (HER2) were seen in 25 % of the serous-like tumors, and mutations in the PI(3)K/AKT pathways were seen in 93 % of endometrioid tumors. These new findings about endometrial cancer suggest a potential for targeted therapy with lapatinib, a dual inhibitor of epidermal growth factor receptor and HER2 tyrosine kinases. However, the clinical efficacy of lapatinib in phase II clinical trials for the treatment of endometrial cancers was only minimal. In this study, we investigated the signaling changes induced by lapatinib in endometrial cancer, which may improve its therapeutic efficacy in molecularly selected patient groups. We identified one of the final molecular targets of lapatinib to be interstitial collagenase, matrix metallopeptidase 1 (MMP1). Lapatinib suppresses MMP1 through EGFR and HER2, and their downstream ERK and AKT signaling pathways. We also found that the activating protein-1 binding site of MMP1 promoter is required for its transcriptional activation, which may be unique for endometrial cancers. Our results also showed that forced expression of active ERK or active AKT mutants rescued MMP1 expression from lapatinib suppression, further suggesting the importance of molecular selection to find appropriate patients with endometrial cancer for future clinical trials with any targeted therapies.

KEY MESSAGE

MMP1 expression was high in tissues and sera in patients with endometrial cancer. Lapatinib inhibited MMP1 via both HER2 and EGFR signaling pathways. Both AKT and ERK need to be inhibited for efficient MMP1 suppression by lapatinib. Activating protein-1 (AP-1) binding site of MMP1 promoter is uniquely required for MMP1 activation in endometrial cancer. Suppression of both c-fos and c-Jun bound to AP1 binding site is required for lapatinib inhibition.

Biological resonance for cancer metastasis, a new hypothesis based on comparisons between primary cancers and metastases

Many hypotheses have been proposed to try to explain cancer metastasis. However, they seem to be contradictory and have some limitations. Comparisons of primary tumors and matched metastases provide new insight into metastasis. The results show high concordances and minor differences at multiple scales from organic level to molecular level. The concordances reflect the commonality between primary cancer and metastasis, and also mean that metastatic cancer cells derived from primary cancer are quite conservative in distant sites. The differences reflect variation that cancer cells must acquire new traits to adapt to foreign milieu during the course of evolving into a new tumor in second organs. These comparisons also provided new information on understanding mechanism of vascular metastasis, organ-specific metastasis, and tumor dormancy. The collective results suggest a new hypothesis, biological resonance (bio-resonance) model. The hypothesis has two aspects. One is that primary cancer and matched metastasis have a common progenitor. The other is that both ancestors of primary cancer cells and metastatic cancer cells are under similar microenvironments and receive similar or same signals. When their interactions reach a status similar to primary cancer, metastasis will occur. Compared with previous hypotheses, the bio-resonance hypothesis seems to be more applicable for cancer metastasis to explain how, when and where metastasis occurs. Thus, it has important implications for individual prediction, prevention and treatment of cancer metastasis.

St Gallen molecular subtypes in primary breast cancer and matched lymph node metastases--aspects on distribution and prognosis for patients with luminal A tumours: results from a prospective randomised trial

Background

The St Gallen surrogate molecular subtype definitions classify the oestrogen (ER) positive breast cancer into the luminal A and luminal B subtypes according to proliferation rate and/or expression of human epidermal growth factor receptor 2 (HER2) with differences in prognosis and chemo-responsiveness. Primary tumours and lymph node metastases might represent different malignant clones, but in the clinical setting only the biomarker profile of the primary tumour is used for selection of adjuvant systemic treatment. The present study aimed to classify primary breast tumours and matched lymph node metastases into luminal A, luminal B, HER2-positive and triple-negative subtypes and compare the distributions.

Methods

Eighty-five patients with available tumour tissue from both locations were classified. The distribution of molecular subtypes in primary tumours and corresponding lymph node metastases were compared, and related to 5-year distant disease-free survival (DDFS).

Results

The St Gallen molecular subtypes were discordant between primary tumours and matched lymph node metastases in 11% of the patients (p = 0.06). The luminal A subtype in the primary tumour shifted to a subtype with a worse prognostic profile in the lymph node metastases in 7 of 45 cases (16%) whereas no shift in the opposite direction was observed (0/38) (p = 0.02). All subtypes had an increased hazard for developing distant metastasis during the first 5 years after diagnosis in both primary breast tumours and matched lymph node metastases, compared with the luminal A subtype.

Conclusion

The classification according to the St Gallen molecular subtypes in primary tumours and matched lymph node metastases, implicates a shift to a more aggressive subtype in synchronous lymph node metastases compared to the primary breast tumour. The selection of systemic adjuvant therapy might benefit from taking the molecular subtypes in the metastatic node into account.

Biomarker expression and St Gallen molecular subtype classification in primary tumours, synchronous lymph node metastases and asynchronous relapses in primary breast cancer patients with 10 years' follow-up

Molecular profiles of asynchronous breast cancer metastases are of clinical relevance to individual patients' treatment, whereas the role of profiles in synchronous lymph node metastases is not defined. The present study aimed to assess individual biomarkers and molecular subtypes according to the St Gallen classification in primary breast tumours, synchronous lymph node metastases and asynchronous relapses and relate the results to 10-year breast cancer mortality (BCM). Tissue microarrays were constructed from archived tissue blocks of primary tumours (N = 524), synchronous lymph node metastases (N = 147) and asynchronous relapses (N = 36). The samples were evaluated by two independent pathologists according to oestrogen receptor (ER), progesterone receptor (PR), Ki67 and human epidermal growth factor receptor 2 (HER2) by immunohistochemistry and in situ hybridisation. The expression of biomarkers and molecular subtypes in the primary tumour was compared with that in the synchronous lymph node metastases and relapses, and related to 10-year BCM. Discordances were found between primary tumours and relapses (ER: p = 0.006, PR: p = 0.04, Ki67: p = 0.02, HER2: p = 0.02, St Gallen subtypes: p = 0.07) but not between primary tumours and metastatic lymph node. Prognostic information was gained by the molecular subtype classification in primary tumours and nodal metastases; triple negative subtype had the highest BCM compared with the luminal A subtype (primary tumours: HR 4.0; 95 % CI 2.0-8.2, p < 0.001, lymph node metastases: HR 3.5; 95 % CI 1.3-9.7, p = 0.02). When a shift in subtype inherence between primary tumour and metastatic lymph node was identified, the prognosis seemed to follow the subtype of the lymph node. Molecular profiles are not stable throughout tumour progression in breast cancer. Prognostic information for individual patients appears to be available from the analysis of biomarker expression in synchronous metastatic lymph nodes. The study supports biomarker analysis also in asynchronous relapses.

HER2 discordance between primary and metastatic breast cancer: assessing the clinical impact

BACKGROUND

In the setting of breast cancer relapse, treatment decisions are typically made by utilizing HER2, estrogen, and progesterone receptor expression status of the primary breast cancer. Recently, concern regarding receptor discordance has led to recommendations for rebiopsy for all cases of metastatic disease. However, whether this is an appropriate recommendation is uncertain, particularly as the clinical implications for HER2 discordance are unknown.

METHODS

We performed a literature review to identify studies assessing HER2 discordance between primary and metastatic breast cancer. These studies were then reviewed for data relating to (1) impact of clinical factors on discordance rates, (2) prognostic impact of discordance, or (3) clinical outcomes from treatment alteration due to receptor discordance. Results were analyzed qualitatively.

RESULTS

From 60 HER2 discordance studies identified, 24 contained information of interest for this review. No clear factor promoting HER2 discordance was identified. Loss of HER2 seemed to result in worse post-relapse survival and overall survival, although these data were often confounded by lack of treatment in the setting of receptor loss. Conversely, HER2 discordance was not associated with shorter DFS. Individual patients with receptor gain appear to have benefited from addition of targeted treatment, although data are limited to case reports.

CONCLUSION

Evidence of HER2 discordance leading to alterations in patient outcomes is limited, highlighting the need for further research in this area. Furthermore, lack of alteration in patient outcomes suggests that a more pragmatic approach to the decision to rebiopsy may be appropriate.

Differential expression of prognostic proteomic markers in primary tumour, venous tumour thrombus and metastatic renal cell cancer tissue and correlation with patient outcome

Renal cell carcinoma (RCC) is the most deadly of urological malignancies. Metastatic disease affects one third of patients at diagnosis with a further third developing metastatic disease after extirpative surgery. Heterogeneity in the clinical course ensures predicting metastasis is notoriously difficult, despite the routine use of prognostic clinico-pathological parameters in risk stratification. With greater understanding of pathways involved in disease pathogenesis, a number of biomarkers have been shown to have prognostic significance, including Ki67, p53, vascular endothelial growth factor receptor 1 (VEGFR1) and ligand D (VEGFD), SNAIL and SLUG. Previous pathway analysis has been from study of the primary tumour, with little attention to the metastatic tumours which are the focus of targeted molecular therapies. As such, in this study a tissue microarray from 177 patients with primary renal tumour, renal vein tumour thrombus and/or RCC metastasis has been created and used with Automated Quantitative Analysis (AQUA) of immunofluorescence to study the prognostic significance of these markers in locally advanced and metastatic disease. Furthermore, this has allowed assessment of differential protein expression between the primary tumours, renal vein tumour thrombi and metastases. The results demonstrate that clinico-pathological parameters remain the most significant predictors of cancer specific survival; however, high VEGFR1 or VEGFD can predict poor cancer specific survival on univariate analysis for locally advanced and metastatic disease. There was significantly greater expression of Ki67, p53, VEGFR1, SLUG and SNAIL in the metastases compared with the primary tumours and renal vein tumour thrombi. With the exception of p53, these differences in protein expression have not been shown previously in RCC. This confirms the importance of proliferation, angiogenesis and epithelial to mesenchymal transition in the pathogenesis and metastasis of RCC. Importantly, this work highlights the need for further pathway analysis of metastatic tumours for overcoming drug resistance and developing new therapies.

Sample parameters affecting the clinical relevance of RNA biomarkers in translational breast cancer research

In the frame of translational breast cancer research, eligibility criteria for formalin-fixed paraffin-embedded tissue (FFPE) material processing for gene expression studies include tumor cell content (TCC) and sample site (primary vs metastatic tumors). Herein we asked whether the observed differences in gene expression between paired samples with respect to TCC and sample site also have different clinical significance. We assessed ESR1, ERBB2, MAPT, MMP7, and RACGAP1 mRNA expression with real time PCR in paired samples before (NMD) and after macrodissection (MD) from 98 primary tumors (P_MD, P_NMD) and 72 metastatic lymph nodes (LN_MD, LN_NMD), as well as from 93 matched P (mP) and LN (mLN). TCC range was 2.5–75 % in the NMD series and 28–98 % in the MD and in the mP/mLN series. The prognostic effect of these markers, individually or in clusters, remained stable between paired P_MD/NMD. In comparison, cluster classification failed in the LN_NMD group with lower TCC. In the mP/mLN cohort, RACGAP1 mRNA expression was of prognostic significance when tested in mLN samples (p < 0.001). Similarly, luminal B, HER2, and triple negative tumors were of dismal prognosis when classified in the LN component of the same series (mLN, overall survival: p = 0.013, p = 0.034, and p = 0.007, respectively). In conclusion, the clinical relevance of the RNA markers examined may be affected by TCC in metastatic LN samples but not in primary tumors, while it differs between primary tumors and matched metastases. These data will facilitate the design of translational studies involving FFPE sample series.

Expression of epithelial to mesenchymal transition-related markers in lymph node metastases as a surrogate for primary tumor metastatic potential in breast cancer

Background

Breast cancers are phenotypically and genotypically heterogeneous tumors containing multiple cancer cell populations with various metastatic potential. Aggressive tumor cell subpopulations might more easily be captured in lymph nodes metastases (LNM) than in primary tumors (PT). We evaluated mRNA and protein levels of master EMT regulators: TWIST1, SNAIL and SLUG, protein levels of EMT-related markers: E-cadherin, vimentin, and expression of classical breast cancer receptors: HER2, ER and PgR in PT and corresponding LNM. The results were correlated with clinicopathological data and patients outcomes.

Methods

Formalin-fixed paraffin-embedded samples from PT and matched LNM from 42 stage II-III breast cancer patients were examined. Expression of TWIST1, SNAIL and SLUG was measured by reverse-transcription quantitative PCR. Protein expression was examined by immunohistochemistry on tissue microarrays. Kaplan-Meier curves for disease-free survival (DFS) and overall survival (OS) were compared using F-Cox test. Hazard ratios (HRs) with 95% confidence intervals (95% CI) were computed using Cox regression analysis.

Results

On average, mRNA expression of TWIST1, SNAIL and SLUG was significantly higher in LNM compared to PT (P < 0.00001 for all). Gene and protein levels of TWIST1, SNAIL and SLUG were highly discordant between PT and matched LNM. Increased mRNA expression of TWIST1 and SNAIL in LNM was associated with shorter OS (P = 0.04 and P = 0.02, respectively) and DFS (P = 0.02 and P = 0.01, respectively), whereas their expression in PT had no prognostic impact. Negative-to-positive switch of SNAIL protein correlated with decreased OS and DFS (HR = 4.6; 1.1-18.7; P = 0.03 and HR = 3.8; 1.0-48.7; P = 0.05, respectively).

Conclusions

LNM are enriched in cells with more aggressive phenotype, marked by elevated levels of EMT regulators. High expression of TWIST1 and SNAIL in LNM, as well as negative-to-positive conversion of SNAIL confer worse prognosis, confirming the correlation of EMT with aggressive disease behavior. Thus, molecular profiling of LNM may be used as surrogate marker for aggressiveness and metastatic potential of PT.

Variability in hormone and growth factor receptor expression in primary versus recurrent, metastatic, and post-neoadjuvant breast carcinoma

The introduction of selective molecular targeted therapy, specifically tamoxifen and trastuzumab, has significantly altered the clinical behavior of breast carcinoma. Several questions remain, however, regarding potential phenotypic drifts in estrogen receptor (ER), progesterone receptor (PR), and epidermal growth factor receptor (Her-2/neu) expression between the primary and metastatic site. Whether patients should be tested for ER, PR, and Her-2/neu expression in the nodal or distant metastatic site, local recurrence and following neoadjuvant therapy, and whether this has an effect on prognosis remains elusive. A review of 45 studies addressing ER, PR, and Her-2/neu expression in lymph node metastasis, distant metastasis, local recurrence, and post-neoadjuvant therapy revealed the following average phenotypic drift in ER, PR, and Her-2/neu expression, respectively: 13.1 % (median = 10.0 %), 13.8 % (median = 16.0 %), and 7.7 % (median = 5.0 %) for lymph node metastasis; 21.8 % (median = 19.5 %), 30.8 % (median = 33.5 %), and 7.6 % (median = 6.1 %) for distant metastasis; 19.8 % (median = 13.4 %), 27.1 % (median = 28.6 %), and 6.6 % (median = 1.6 %) for local recurrence; and 12.9 % (median = 8.0 %), 32.0 % (median = 20.0 %), and 8.9 % (median = 0 %) post-neoadjuvant therapy. The above findings support the notion of re-evaluating ER, PR, and Her-2/neu expression in distant metastasis, lymph node metastasis and to a lesser extent local recurrence. The effects of neoadjuvant therapy on receptor expression are more pronounced for PR, which may have a prognostic role in therapy efficacy.

Collision metastasis of breast and thyroid carcinoma to a single cervical lymph node: report of a case

We herein report a rare case of collision lymph node metastases of breast and thyroid carcinomas. A 49-year-old female had undergone an extensively radical mastectomy of the right breast for inflammatory breast cancer at our hospital. Eleven months later, she presented with enlarged lymph nodes in her right lateral neck and multiple nodules in bilateral thyroid lobes. The patient underwent total thyroidectomy and radical dissection of the bilateral cervical lymph nodes. A histological examination showed multiple foci of papillary thyroid carcinoma (PTC) in the bilateral lobes. Surprisingly, concurrent metastases of breast carcinoma and PTC were shown in one of the lymph nodes from the right jugular region. This rare case of collision metastasis and the related literature are discussed.

Loss of human epidermal growth factor receptor 2 (HER2) expression in metastatic sites of HER2-overexpressing primary breast tumors

PURPOSE

We evaluated whether patients with human epidermal growth factor receptor 2 (HER2) -positive primary breast tumors had metastatic tumors that were HER2 positive (concordant) or HER2 negative (discordant). We then evaluated whether treatment with trastuzumab or chemotherapy before biopsy of the metastasis had any effect on the rate of HER2 discordance. We also compared the overall survival durations of patients with HER2-concordant and -discordant tumors.

PATIENTS AND METHODS

We retrospectively identified all patients who initially had been diagnosed with HER2-positive (immunohistochemistry 3+ and/or fluorescent in situ hybridization positive) primary breast cancer between 1997 and 2008 at MD Anderson Cancer Center who also had metastatic tumor biopsy results available for review.

RESULTS

We included 182 patients who met our criteria. Forty-three (24%) of the 182 patients with HER2-positive primary tumors had HER2-negative metastatic tumors. The HER2 discordance rates differed significantly on the basis of whether patients received chemotherapy (P = .022) but not on the basis of whether patients received trastuzumab (P = .296). Patients with discordant HER2 status had shorter overall survival than did patients with concordant HER2 status (hazard ratio [HR], 0.43; P = .003). A survival difference remained among the 67 patients who received trastuzumab (HR, 0.56; P = .083) and 101 patients who did not (HR, 0.53; P = .033) before their metastasis biopsies.

CONCLUSION

We confirmed that loss of HER2-positive status in metastatic tumors can occur in patients with primary HER2-positive breast cancer. Our data strongly support the need for biopsies of metastatic lesions to accurately determine patient prognosis and appropriate use of targeted therapy.

[Hormone receptors and HER-2 changes during breast cancer progression: clinical implications]

Breast cancer remains a major public health problem. Even if there is an increase in this cancer curability, metastatic breast cancer remains a lethal disease in the vast majority of cases. Therapeutic advances in the chemotherapeutic and targeted therapies fields induced an increase in survival, however the proportion of long survivors remains low. Phenotypic instability, an early process initiated during tumour progression, and continued on the metastatic stage of the disease, can be one of the putative hypotheses explaining these results. An increasing amount of scientific data are pledging for a reanalysis of the phenotypic profile regarding hormone receptors and HER-2 status of metastatic lesions in order to identify drugable targets and allow individualisation of the treatment of these metastatic breast cancer patients. Phenotypic changes between the primary tumour and the paired metastatic lymph nodes are a challenging pitfall, raising the question of which site has to be assessed in the adjuvant treatment decision process. This article presents a comprehensive analysis of the frequency of theses phenotypic changes altogether with new modalities to evaluate this phenotypic status.

HER2 discordance between primary breast cancer and its paired metastasis: tumor biology or test artefact? Insights through meta-analysis

The proto-oncogene, HER2, has prognostic and predictive relevance in invasive breast cancer (IBC). HER2 testing of primary IBC guides treatment selection and is assumed to reflect HER2 status of associated metastases, although HER2 discordance between IBC and metastasis has been reported. Systematic review and meta-analysis of HER2 status in IBC and its paired loco-regional or distant metastasis were done. Quality appraisal considered whether (within-subject) testing conditions were maintained for paired primary and metastasis. Random effects logistic regression models were used to estimate pooled within-subject HER2 discordant proportions and to examine study-level covariates, including tumor-related and testing-related variables, potentially associated with HER2 discordance differences across (between) studies. Modelled paired HER2 data for primary and metastatic cancer (2520 subjects, 26 studies) showed a pooled HER2 discordance of 5.5% (3.6-8.5%). Sensitivity analysis, excluding the only study not maintaining same conditions for paired testing, gave a pooled estimate of 5.2% (3.5-7.8%). Pooled discordant proportion was not associated with differences between studies in test type, test scoring or interpretation criteria, subjects' median age, study time-frame, or HER2 positivity in primary cancer (all P > 0.05). However, type of metastasis was significantly associated with estimated HER2 discordance (P = 0.0017): studies of primary tumor paired with distant metastases had higher discordance [11.5% (6.9-18.6%)] than studies of primary paired with lymph node metastases only [4.1% (2.4-7.2%)], or those paired with nodal or various metastases [3.3% (2.0-5.6%)]; P < 0.01. HER2 discordant proportion was higher where paired metastases were metachronous relative to synchronous to primary IBC (P = 0.0024). Sensitivity analysis provided weak evidence (P = 0.074) that discordance in the direction of change from HER2-negative primary cancer to HER2-positive paired metastasis was more likely than the reverse. Study-level meta-analysis suggests factors associated with the type of metastasis as underlying mechanisms for observed HER2 discordance between primary IBC and paired metastasis. Test-related factors did not account for differences across studies in the HER2 discordant proportion.

ER, HER2, and TOP2A expression in primary tumor, synchronous axillary nodes, and asynchronous metastases in breast cancer

At recurrence of breast cancer, the therapeutic target is the metastases. However, it is current practice to base the choice of systemic treatment on the biomarker profile of the primary tumor. In the present study, confirmatory biopsies were obtained from suspected metastatic lesions and compared with the primary tumors with respect to ER, HER2, and TOP2A. In the prospective tissue-collection study, 81 patients had biopsy from a suspected relapse. Additional archived paired material was included, leaving a total of 119 patients with paired primary tumor, synchronous axillary nodes (available in 52 patients) and asyncronous metastases available for analysis. ER, HER2, and TOP2A expression of primary tumors, axillary nodes and metastases were re-analysed and determined centrally by immunohistochemistry, chromogenic in situ hybridization, and fluorescence in situ hybridization. Of the 81 patients with a biopsy from a suspected relapse, 65 (80%) were diagnosed with recurrent breast carcinoma, 3 (4%) were diagnosed with other malignancies, 6 (7%) had benign conditions, and in 7 (9%) patients the biopsy was non-representative. Discordance in ER, HER2, and TOP2A (aberration vs. normal) status between primary tumor and corresponding asynchronous metastasis was 12% (14/118), 9% (10/114), and 23% (17/75), respectively. There were no significant associations with biomarker discordance and prior adjuvant therapy, or location of biopsy. Expression of ER, HER2, and TOP2A displayed discordance with a sufficient frequency to emphasize the role of confirmatory biopsies from metastatic lesions in future management of recurrent breast cancer.

Heterogeneity of Bcl-2 expression in metastatic breast carcinoma

Bcl-2 is an antiapoptotic protein that promotes cell survival, but also may block proliferation. In breast cancer, bcl-2 expression correlates with favorable prognosis and estrogen receptor (ER) positivity. However, experimental data have paradoxically suggested that bcl-2 promotes chemoresistance and metastasis. A direct and comprehensive comparison of bcl-2 expression between primary breast carcinomas and paired distant metastases has not been performed. We completed rapid autopsies on 17 patients with archived primary tumors and metastatic breast carcinoma, and created single-patient tissue microarrays containing each patient's primary tumor and matched metastases. Expression of bcl-2, ER, progesterone receptor, and HER-2 in primary tumors and matched metastases were compared by immunohistochemistry. All 11 ER-positive cases showed bcl-2 labeling in the primary tumor, whereas only 3 of 6 ER-negative cases did (P=0.029). In 10 cases, bcl-2 labeling in metastases was similar to that of the primary, although 3 cases showed significant variation among metastases. In six other cases, bcl-2 labeling was lost or significantly diminished in metastases. Five of the latter cases were Luminal A (ER-positive, HER-2-negative) primaries, three of which lost hormone receptors in metastases. Only 1 of 17 cases showed an increase in bcl-2 labeling in metastases compared with the paired primary tumor. In conclusion, bcl-2 is infrequently upregulated in metastatic breast carcinoma. Instead, downregulation of bcl-2 expression may occur in the setting of hormone therapy resistance. Our findings call into question the potential utility of anti-bcl-2 therapy in metastatic breast cancer.

HER2-mediated upregulation of MMP-1 is involved in gastric cancer cell invasion

HER2 overexpression is associated with metastasis-the main cause of death in individuals with gastric cancer. In this study, we demonstrated that vector-based shRNA significantly knocked down the expression of HER2 and considerably inhibited both the migration and invasion of gastric cancer cells. HER2 knockdown resulted in the downregulation of the expression of MMP-1, while HER2 overexpression improved the transcription of MMP-1 through the activation of an MMP-1 promoter. The promoter region of MMP-1 between -2500 and -2000 bp was found to be crucial for the upregulation of HER2-mediated transcription. Furthermore, a truncated promoter (-70 to+63) did not display any transcriptional activity. Cell invasion activity was almost completely inhibited when MMP-1 was knocked down. Conversely, the overexpression of MMP-1 partly rescued the invasion ability of cell strains with knocked-down HER2. These findings help further understanding of the molecular mechanisms through which HER2 promotes malignancy, and suggest that targeting both HER2 and MMP-1 may be required to effectively block HER2 signaling in gastric cancer therapy.

Estrogen receptor and HER2/neu status affect epigenetic differences of tumor-related genes in primary breast tumors

Introduction

Estrogen receptor (ER)-positive breast cancers are considered prognostically more favorable than ER-negative tumors, whereas human epidermal growth factor receptor (HER)2/neu-positive breast cancers are associated with worse prognosis. The objective of the present study was to determine whether ER-positive and ER-negative status relates to epigenetic changes in breast cancer-related genes. To evaluate epigenetic differences in tumor-related genes relating to ER and HER2/neu status of primary tumors, we examined the promoter methylation status of the promoter region CpG islands of eight major breast tumor-related genes (RASSF1A, CCND2, GSPT1, TWIST, APC, NES1, RARβ2, and CDH1).

Methods

Paired ER-positive (n = 65) and ER-negative (n = 65) primary breast tumors (n = 130) matched for prognostic factors were assessed. DNA was extracted from paraffin-embedded tumor tissue after microdissection, and methylation-specific PCR and capillary-array electrophoresis analysis were performed.

Results

In early stages of tumor progression (T1 and N0), RASSF1A and CCND2 were significantly (P < 0.05) more methylated in ER-positive than in ER-negative tumors. GSTP1 hypermethylation was more frequent in the lymph node metastasis positive group than in the negative group. Double negative (ER-negative, HER2/neu-negative) breast cancers had significantly lesser frequencies of RASSF1A, GSTP1, and APC methylation (P < 0.0001, P < 0.0001, and P = 0.0035, respectively). Both ER and HER2/neu status correlated independently with these epigenetic alterations.

Conclusion

We demonstrated significant differences in tumor-related gene methylation patterns relevant to ER and HER2/neu status of breast tumors. This may be of significance in the assessment of targeted therapy resistance related to ER and HER2/neu status in breast cancer patients.

Nm23-H1 expression of metastatic tumors in the lymph nodes is a prognostic indicator of oral squamous cell carcinoma

We recently reported that low Nm23-H1 expression of primary oral squamous cell carcinoma (OSCC) was correlated with the occurrence of lymphatic metastasis. However, little is known about whether Nm23-H1 level of metastatic tumors in the cervical lymph nodes is reduced in comparison with primary oral cancers and its significance for patients' prognosis. By immunohistochemistry, we analyzed the Nm23-H1 expression in 52 pairs of OSCC specimens from primary oral cancers and their metastatic lymph nodes. Western blot analysis further confirmed the immunohistochemical interpretation. To verify the effects of Nm23-H1 on cell migration and invasion, we established several stable clones derived from a human OSCC cell line (SAS) by knockdown and overexpression. Wound-healing closure, transwell migration and invasion assays were performed to determine cell motility, migratory and invasive activities. Western blot analysis was carried out to evaluate cyclin A expression of OSCC cells with the altered Nm23-H1 levels following knockdown and overexpression. By immunohistochemistry, Nm23-H1 expression of metastatic lymph nodes was significantly lower than that of their primary oral cancers, supporting a role of Nm23-H1 in metastasis suppression. Negative Nm23-H1 interpretation of OSCC specimens, in either primary oral cancers or metastatic lymph nodes, indicated a poor survival outcome of patients. On the basis of in vitro studies of Nm23-H1 knockdown and overexpression, we demonstrated an inverse correlation between Nm23-H1 expression and the invasiveness of OSCC cells. Moreover, we observed the concomitant reduction in Nm23-H1 and cyclin A levels of metastatic tumors in both results of in vitro OSCC cells and ex vivo tumor specimens.

Selecting differentially expressed genes using minimum probability of classification error

Discovery of differentially expressed genes between normal and diseased patients is a central research problem in bioinformatics. It is specially important to find few genetic markers which can be explored for diagnostic purposes. The performance of a set of markers is often measured by the associated classification accuracy. This motivates our ranking of genes depending on the minimum probability of classification errors (MPE) for each gene. In this work, we use Bayesian decision-making algorithm to compute MPE. A quantile-based probability density estimation technique is used for generating probability density functions of genes. The method is tested on three datasets: colon cancer, leukaemia, and hereditary breast cancer. The quality of the selected markers is evaluated by the classification accuracy obtained using support-vector-machine and a modified naive Bayes classifier. We obtain 96.77% accuracy in colon cancer and 97.06% accuracy in leukaemia, using only five genes in each case. Finally, using just three genes we get 100% accuracy in hereditary breast cancer. We also compare our results with those using the genes ranked by p-value and show that the genes ranked by MPE perform better or equal to those ranked by p-value.