Bone marrow cytokeratin 19 mRNA level is an independent predictor of relapse-free survival in operable breast cancer patients

Prognostic value of disseminated tumor cells in unresectable pancreatic ductal adenocarcinoma: a prospective observational study

BACKGROUND

Although pancreatic ductal adenocarcinoma (PDAC) rarely metastasizes to the skeleton, disseminated tumor cells have been detected in bone marrow samples from patients with this disease. The prognostic value of such findings is currently unclear. Thus, the current study aimed to clarify the prognostic information associated with disseminated tumor cell detection in samples from patients with PDAC.

METHODS

Bone marrow aspirates were obtained from 48 patients with locally advanced (n = 11) or metastatic (n = 37) PDAC, before and after 2 months of chemotherapy. Disseminated tumor cells were detected with an mRNA panel and quantitative reverse transcription PCR. We used the highest levels measured in healthy bone marrow (n = 30) as a threshold to define the positive detection of disseminated tumor cells. Progression-free and overall survival were analyzed with Kaplan-Meier and Cox proportional hazards regression analyses.

RESULTS

Disseminated tumor cells were detected in 15/48 (31%) bone marrow samples obtained before starting chemotherapy and in 8/25 (32%) samples obtained during chemotherapy. Patients with disseminated tumor cells detected before therapy had significantly shorter progression-free (p = 0.03; HR = 2.0) and overall survival (p = 0.03; HR = 2.0), compared to those without disseminated tumor cells in the bone marrow. When restricting disseminated tumor cell detection to keratins KRT7 and KRT8, the prognostic information was substantially stronger (p = 1 × 10-6; HR = 22, and p = 2 × 10-5; HR = 7.7, respectively). The multivariable Cox regression analysis demonstrated that disseminated tumor cell detection prior to treatment had independent prognostic value. In contrast, disseminated tumor cells detected during treatment did not have prognostic value.

CONCLUSIONS

Disseminated tumor cells detected before commencing chemotherapy had prognostic value in patients with inoperable PDAC.

Detection of disseminated tumor cells in bone marrow predict late recurrences in operable breast cancer patients

BACKGROUND

Operable breast cancer patients may experience late recurrences because of reactivation of dormant tumor cells within the bone marrow (BM). Identification of patients who would benefit from extended therapy is therefore needed.

METHODS

BM samples obtained pre- and post-surgery were previously analysed for presence of disseminated tumor cells (DTC) by a multimarker mRNA quantitative reverse-transcription PCR assay. Updated survival analyses were performed on all patient data (n = 191) and in a subgroup of patients alive and recurrence-free after 5 years (n = 156). DTC data were compared to the mitotic activity index (MAI) of the primary tumors. Median follow-up time was 15.3 years.

RESULTS

Among the 191 patients, 49 (25.65%) experienced systemic relapse, 24 (49%) within 5-18 years after surgery. MAI and pre- and post-operative DTC status had significant prognostic value based on Kaplan-Meier analyses and multiple Cox regression in the overall patient cohort. With exclusion of patients who relapsed or died within 5 years from surgery, only pre-operative DTC detection was an independent prognostic marker of late recurrences. High MAI (≥10) did not predict late recurrences or disease-specific mortality.

CONCLUSION

Pre-operative DTC detection, but not MAI status, predicts late recurrences in operable breast cancer.

Different prognostic value of circulating and disseminated tumor cells in primary breast cancer: Influence of bisphosphonate intake?

Disseminated tumor cells (DTCs) in the bone marrow (BM) and circulating tumor cells (CTCs) in blood of breast cancer patients (pts) are known to correlate with worse outcome. Here we demonstrate a different prognostic value of DTCs and CTCs and explain these findings by early clodronate intake. CTCs (n = 376 pts) were determined using the AdnaTest BreastCancer (Qiagen Hannover GmbH, Germany) and DTCs (n = 525 pts) were analyzed by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3. Clodronate intake was recommended in case of DTC-positivity. CTCs were detected in 22% and DTCs in 40% of the pts, respectively. DTCs were significantly associated with nodal status (p = 0.03), grading (p = 0.01), lymphangiosis (p = 0.03), PR status (p = 0.02) and clodronate intake (p < 0.0001), no significant associations were demonstrated for CTCs. CTCs significantly correlated with reduced PFS (p = 0.0227) and negative prognostic relevance was predominantly related to G2 tumors (p = 0.044), the lobular (p = 0.024) and the triple-negative subtype (p = 0.005), HR-negative pts (p = 0.001), postmenopausal women (p = 0.013) and patients who had received radiation therapy (p = 0.018). No prognostic significance was found for DTCs. Therefore early clodronate intake can improve prognosis of breast cancer patients and CTCs might be a high risk indicator for the onset of metastasis not limited to bone metastasis.

Comparison of molecular and immunocytochemical methods for detection of disseminated tumor cells in bone marrow from early breast cancer patients

BACKGROUND

Disseminated tumor cells (DTCs) have potential to predict the effect of adjuvant treatment. The purpose of this study was to compare two methods, reverse transcription quantitative PCR (RT-qPCR) and immunocytochemisty (ICC), for detecting breast cancer DTCs in bone marrow (BM) from early breast cancer patients.

METHODS

We investigated a subset (n = 313) of BM samples obtained from 271 early breast cancer patients in the "Secondary Adjuvant Taxotere Treatment" (SATT)-trial. All patients in this study had node positive or intermediate/high-risk node negative non-metastatic disease. The DTCs were detected by ICC using AE1-AE3 anti-cytokeratin monoclonal antibodies. Patients with DTCs detected in their BM by ICC after standard adjuvant fluorouracil, cyclophosphamide, epirubicin (FEC) chemotherapy were offered docetaxel treatment. For comparison, 5 × 106 mononuclear cells from the aliquoted BM samples were also analyzed by RT-qPCR using a multimarker (MM) assay based on the tumor cell mRNA markers keratin 19 (KRT19), mammaglobin A (hMAM), and TWIST1. In the MM-assay, a sample was defined as positive for DTCs if at least one of the mRNA markers was positive.

RESULTS

The MM RT-qPCR assay identified DTCs in 124 (40%) of the 313 BM samples compared with 23/313 (7%) of the samples analyzed by ICC. The concordance between the MM RT-qPCR and ICC was 61% (Kappa value = 0.04) and twelve of the BM samples were positive by both methods. By RT-qPCR, 46/313 (15%) samples were positive for KRT19, 97/313 (31%) for TWIST1, and 3/313 (1%) for hMAM mRNA. There were no statistically significant associations between the individual mRNA markers.

CONCLUSION

The RT-qPCR based method demonstrated more DTC-positive samples than ICC. The relatively low concordance of positive DTC-status between the two different assessment methods suggests that they may be complementary. The clinical relevance of the methods will be evaluated based on future clinical outcome data.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00248703.

Detection of disseminated tumor cells in the bone marrow of breast cancer patients using multiplex gene expression measurements identifies new therapeutic targets in patients at high risk for the development of metastatic disease

Disseminated tumor cells (DTCs) detected in the bone marrow (BM) of breast cancer patients identify women at high risk of recurrence. DTCs are traditionally detected by immunocytochemical staining for cytokeratins or single gene expression measurements, which limit both specificity and sensitivity. We evaluated the Nanostring nCounter™ platform for multi-marker, gene expression-based detection and classification of DTCs in the BM of breast cancer patients. Candidate genes exhibiting tumor cell-specific expression were identified from microarray datasets and validated by qRT-PCR analysis in non-malignant human BM and identical samples spiked with predefined numbers of molecularly diverse breast tumor cell lines. Thirty-eight validated transcripts were designed for the nCounter™ platform and a subset of these transcripts was technically validated against qRT-PCR measurements using identical spiked BM controls. Bilateral iliac crest BM aspirates were collected and analyzed from twenty breast cancer patients, prior to neoadjuvant therapy, using the full 38-gene nCounter™ code set. Tumor cell-specific gene expression by nCounter™ was detected with a sensitivity of one cancer cell per 1 × 10(6) nucleated BM cells after optimization. Measurements were quantitative, log linear over a 20-fold range, and correlated with qRT-PCR measurements. Using the nCounter™ 38-gene panel, 6 of 8 patients (75 %) who developed metastatic disease had detectable expression of at least one transcript. Notably, three of these patients had detectable expression of ERBB2 in their BM, despite the fact that their corresponding primary tumors were HER2/ERBB2 negative and therefore did not receive trastuzumab therapy. Four of these patients also expressed the PTCH1 receptor, a newly recognized therapeutic target based on hedgehog signaling pathway inhibition. The presumptive detection and classification of DTCs in the BM of breast cancer patients, based on sensitive and quantitative multi-marker detection of gene expression using the nCounter™ platform, provide an opportunity to both predict early distant recurrence and, more importantly, identify opportunities for preventing the spread of disease based on the expression of unique, therapeutically actionable gene targets. This study demonstrates the application of a new technology for multiplexed gene expression-based detection of DTCs in the BM of breast cancer patients and identifies at least two therapeutically targetable genes that are frequently expressed in the BM of patients who develop metastatic disease.

Analysis of and prognostic information from disseminated tumour cells in bone marrow in primary breast cancer: a prospective observational study

Background

Disseminated tumour cells (DTCs) in the bone marrow of patients with breast cancer have been identified as an independent predictor of poor prognosis in patients with non-metastatic disease. This prospective study aimed to evaluate the presence and prognostic value of DTCs in the bone marrow of female patients with primary breast cancer.

Methods

Between 1999 and 2003, bone marrow aspirates were obtained from patients at the time of surgery for primary invasive breast cancer. DTCs in bone marrow were identified using monoclonal antibodies against cytokeratins for detection of epithelial cells. The detection of DTCs was related to clinical follow-up with distant disease-free survival (DDFS) and breast cancer-specific survival as endpoints. Bone marrow aspirates from adult healthy bone marrow donors were analysed separately.

Results

DTCs were analysed in 401 patients, and cytokeratin-positive cells were found in 152 of these (38%). An immunofluorescence (IF) staining procedure was used in 327 patients, and immunocytochemistry (IC) was performed in 74 patients. The IF-based method resulted in 40% DTC-positive cases, whereas 30% were positive using IC (p = 0.11). The presence of DTCs in bone marrow was not significantly related to patient or tumour characteristics. The presence of DTCs was not a prognostic factor for DDFS (IF: hazards ratio [HR], 2.2; 95% confidence interval [CI], 0.63–2.2; p = 0.60; IC: HR, 0.84; 95% CI, 0.09–8.1; p = 0.88). Significant prognostic factors were lymph node metastases, oestrogen receptor positivity, Nottingham histological grade, and tumour size using Cox univariate analysis. The analyses were positive for epithelial cells in bone marrow from adult healthy donors in 19 (25%) samples.

Conclusions

The detection of DTCs in bone marrow in primary breast cancer was previously shown to be a predictor of poor prognosis. We were not able to confirm these results in a prospective cohort including unselected patients before the standard procedure was established. Future studies with a standardised patient protocol and improved technique for isolating and detecting DTCs may reveal the clinical applications of DTC detection in patients with micrometastases in the bone marrow.

Persistent tumor cells in bone marrow of non-metastatic breast cancer patients after primary surgery are associated with inferior outcome

Background

To investigate the prognostic significance of disseminated tumor cells (DTCs) in bone marrow (BM) from non-metastatic breast cancer patients before and after surgery.

Methods

Patients with non-metastatic breast cancer were consecutively recruited to this project during the years 1998–2000. Real-time RT-PCR quantification of a DTC multimarker panel consisting of cytokeratin 19, mammaglobin A and TWIST1 mRNA was performed in BM samples obtained from 154 patients three weeks (BM2) and/or six months after surgery (BM3). The results were compared to previously published data from pre-operative BM analyses for the same patients.

Results

DTCs were identified in post-operative BM samples (BM2 and/or BM3) from 23 (15%) of the 154 patients investigated. During a median follow-up of 98 months, 10 (44%) of these patients experienced systemic relapse as compared to 16 (12%) of 131 DTC-negative patients. Kaplan-Meier estimates of systemic recurrence-free- and breast-cancer specific survival demonstrated significantly shorter survival for patients with persistent DTCs in BM after surgery (p≤0.001). By multivariate Cox regression analyses, persistent DTCs after surgery was an independent predictor of both systemic recurrence-free- (HR = 5.4, p < 0.001) and breast-cancer specific survival (HR = 5.3, p < 0.001). Furthermore, the prognostic value of DTCs in BM was similar for pre- and post surgery samples. However, patients with DTCs both before and after surgery (BM1 and BM2/3) had a particularly poor prognosis (systemic recurrence-free survival: HR = 7.2, p < 0.0001 and breast-cancer specific survival: HR = 8.0, p < 0.0001).

Conclusions

Detection of persistent DTCs in BM samples obtained after surgery identified non-metastatic breast cancer patients at high risk for systemic relapse, and with reduced breast-cancer specific survival. Furthermore, patients with positive DTC status both before and after surgery had a particularly poor prognosis.

The presence of disseminated tumour cells in the bone marrow is inversely related to circulating free DNA in plasma in breast cancer dormancy

BACKGROUND

The aim of this study was to gain insight into breast cancer dormancy by examining different measures of minimal residual disease (MRD) over time in relation to known prognostic factors.

METHODS

Sixty-four primary breast cancer patients on follow-up (a median of 8.3 years post surgery) who were disease free had sequential bone marrow aspirates and blood samples taken for the measurement of disseminated tumour cells (DTCs), circulating tumour cells (CTCs) by CellSearch and qPCR measurement of overlapping (96-bp and 291-bp) amplicons in circulating free DNA (cfDNA).

RESULTS

The presence of CTCs was correlated with the presence of DTCs measured by immunocytochemistry (P=0.01) but both were infrequently detected. Increasing cfDNA concentration correlated with ER, HER2 and triple-negative tumours and high tumour grade, and the 291-bp amplicon was inversely correlated with DTCs measured by CK19 qRT-PCR (P=0.047).

CONCLUSION

Our results show that breast cancer patients have evidence of MRD for many years after diagnosis despite there being no overt evidence of disease. The inverse relationship between bone marrow CK19 mRNA and the 291-bp amplicon in cfDNA suggests that an inverse relationship between a measure of cell viability in the bone marrow (DTCs) and cell death in the plasma occurs during the dormancy phase of breast cancer.

Mitotic activity and bone marrow micrometastases have independent prognostic value in node positive breast cancer patients

The purpose of this article is to investigate the prognostic value of the mitotic activity index (MAI) and the presence of disseminated tumor cells (DTCs) in bone marrow (BM), in clinically operable breast cancer patients. We compared routinely assessed MAI, classic prognosticators and BM DTCs, detected by a real-time RT-PCR multimarker assay including cytokeratin 19, mammaglobin A and TWIST1 mRNA, in 179 consecutive patients with operable breast cancer. Over a median follow-up of 96 months (range: 1-126 months), 31 (17.3%) patients experienced a systemic relapse and 26 (14.5%) died of breast cancer-related causes. MAI (≥ 10) was strongly associated with breast cancer-related death in lymph node (LN)-negative patients (hazard ratio (HR): 7.0, confidence interval (CI) 1.74-27.9), whereas both BM DTC-status (HR: 3.3, CI 1.25-8.52) and MAI (HR: 3.1, CI 1.08-8.8) were significant in LN-positive patients. With multivariate Cox regression, MAI was the only significant predictor of breast cancer-specific survival (HR 7.0, CI 1.7-27.9) in LN-negative patients. In LN-positive patients, both BM DTC-status and MAI were strong independent predictors of breast cancer-specific survival (HR 3.3, CI 1.25-8.49 and HR 3.1, CI 1.1-8.9), respectively. Where, however, MAI and BM DTC-status as single parameters were replaced by a combination of these, this showed to be the most significant prognostic marker in both LN-negative (HR 7.7, CI 1.2-50) and LN-positive (HR 6.0, CI 1.4 to 26.4) patients with regard to breast cancer-specific survival. A combination of MAI and BM DTC detection identified both LN-negative and LN-positive breast cancer patients with poor prognosis.

Disseminated tumor cells in bone marrow assessed by TWIST1, cytokeratin 19, and mammaglobin A mRNA predict clinical outcome in operable breast cancer patients

PURPOSE

To investigate the prognostic relevance of disseminated tumor cells (DTCs) in bone marrow (BM) assessed by a multimarker mRNA panel consisting of TWIST1, cytokeratin 19 (CK19) and human mammaglobin A (hMAM) mRNA, in patients with early breast cancer.

PATIENTS AND METHODS

TWIST1 (gene name: TWIST1), CK19 (gene name: KRT19), and hMAM (gene name: SCGB2A2) mRNA was quantitated in BM samples from 191 operable breast cancer patients by real-time reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Using the highest relative mRNA concentration of TWIST1 in the control population as a cut-off, 5 of the 191 breast cancer patients showed elevated TWIST1 mRNA levels in their BM by real-time RT-PCR. Two of these patients experienced a systemic relapse during a median follow-up of 98 months. Combining these results with previous hMAM and CK19 mRNA quantifications in the same BM samples, 12 (40%) of the 30 patients with BM positive for at least 1 marker (multimarker positive) experienced a systemic relapse as compared with 18 (11%) of the 161 patients with multimarker-negative BMs. The patients with multimarker-positive BM had significantly shorter systemic recurrence-free survival (P < .001, log-rank test), breast cancer-specific survival (P < .001), and overall survival (P = .03). The prognostic relevance of BM multimarker detection appeared to be independent of adjuvant treatment, although the difference was not statistically significant in the subgroup of patients who received adjuvant chemotherapy. Multivariate analysis demonstrated the BM multimarker panel status to be a strong independent predictor of clinical outcome.

CONCLUSION

Our results demonstrated the prognostic relevance of BM DTCs assessed by a multimarker mRNA panel consisting of TWIST1, CK19, and hMAM in operable breast cancer patients.

Implications of cancer-associated systemic inflammation for biomarker studies

Highly sensitive molecular technologies provide new capacities for cancer biomarker research, but with sensitivity improvements marker specificity is significantly decreased, and too many false-positive results should disqualify the measurement from clinical use. Hence, of the thousands of potential cancer biomarkers only a few have found their way to clinical application. Differentiating false-positive results from true-positive (cancer-specific) results can indeed be difficult, if validation of a marker is performed against inadequate controls. We present examples of accumulating evidence that not only local but also systemic inflammatory reactions are implicated in cancer development and progression and interfere with the molecular image of cancer disease. We analyze several modern strategies of tumor marker discovery, namely, proteomics, metabonomics, studies on circulating tumor cells and circulating free nucleic acids, or their methylation degree, and provide examples of scarce, methodologically correct biomarker studies as opposed to numerous methodologically flawed biomarker studies, that examine cancer patients' samples against those of healthy, inflammation-free persons and present many inflammation-related biomarker alterations in cancer patients as cancer-specific. Inflammation as a cancer-associated condition should always be considered in cancer biomarker studies, and biomarkers should be validated against their expression in inflammatory conditions.

Prognostic value of nodal ratios in node-positive breast cancer: a compiled update

The number of positive axillary nodes is a strong prognostic factor in breast cancer, but is affected by variability in nodal staging technique yielding varying numbers of excised nodes. The nodal ratio of positive to excised nodes is an alternative that could address this variability. Our 2006 review found that the nodal ratio consistently outperformed the number of positive nodes, providing strong arguments for the use of nodal ratios in breast cancer staging and management. New evidence has continued to accrue confirming the prognostic significance of nodal ratios in various worldwide population settings. This review provides an updated summary of available data, and discusses the potential application of the nodal ratio to breast cancer staging and prognostication, its role in the context of modern surgical techniques such as sentinel node biopsy, and its potential correlations with new biologic markers such as circulating tumor cells and breast cancer stem cells.

Positive bone marrow biopsy is associated with a decreased disease-free survival in patients with operable breast cancer

BACKGROUND

Bone marrow (BM) biopsy has been suggested as an independent prognostic factor in patients with breast cancer.

METHODS

Patients operated for breast cancer from June 2000 to April 2008 were enrolled in this protocol after signing an informed consent. After primary surgery, BM aspirate from the iliac crest was obtained and 5-10 cc of blood collected. Since 2002 a peripheral blood (PB) sample was also obtained. Both carcinoembryonic antigen (CEA) and Mammaglobin-specific nested reverse-transcription polymerase chain reaction (RT-PCR) were used to examine BM and PB samples. Physicians and patients were blinded to results.

RESULTS

Two hundred seventy-three patients underwent BM and/or PB test. The median age of the patients was 63 years (31-80 years), and the median tumor diameter was 1.5 cm (0.1-6 cm). BM aspirates were unsuccessful in nine patients, and RT-PCR was not technically feasible in 18 women, leaving 246 patients available for analysis of results and follow-up. Among them, 110 patients (45%) had either a BM or a PB test positive for CEA or Mammaglobin (Test+). At median follow-up of 60 months, 31 events (deaths or relapse) occurred (13%). Disease-free survival (DFS) was significantly lower in the Test+ group (BP and/or PB) (P<0.001). This effect was independent of nodal status. At 5 years, event-free survival for Node-/Test- patients was 46/49 (94%) and for Node+/Test+ patients was 21/33 (64%), while patients with only one status positive (Node-/Test+ or Node+/Test-) had an intermediate disease-free survival (35/43, 81%) (P=0.005). In a subgroup analysis, RT-PCR results for BM and Mammaglobin retained statistical significance on DFS (P<0.001), while those for PB and CEA did not.

CONCLUSIONS

This study confirms that RT-PCR of the BM is an independent prognostic factor for disease-free survival of breast cancer patients, and may improve their staging, allowing better strategies for therapy and follow-up.

Review: Biological relevance of disseminated tumor cells in cancer patients

The prognosis of cancer patients is largely determined by the occurrence of distant metastases. In patients with primary tumors, this relapse is mainly due to clinically occult micrometastasis present in secondary organs at primary diagnosis but not detectable even with high resolution imaging procedures. Sensitive and specific immunocytochemical and molecular assays enable the detection and characterization of disseminated tumor cells (DTC) at the single cell level in bone marrow (BM) as the common homing site of DTC and circulating tumor cells (CTC) in peripheral blood. Because of the high variability of results in DTC and CTC detection, there is an urgent need for standardized methods. In this review, we will focus on BM and present currently available methods for the detection and characterization of DTC. Furthermore, we will discuss data on the biology of DTC and the clinical relevance of DTC detection. While the prognostic impact of DTC in BM has clearly been shown for primary breast cancer patients, less is known about the clinical relevance of DTC in patients with other carcinomas. Current findings suggest that DTC are capable to survive chemotherapy and persist in a dormant nonproliferating state over years. To what extent these DTC have stem cell properties is subject of ongoing investigations. Further characterization is required to understand the biology of DTC and to identify new targets for improved risk prevention and tailoring of therapy. Our review will focus on breast, colon, lung, and prostate cancer as the main tumor entities in Europe and the United States.

Validating the prognostic value of proliferation measured by Phosphohistone H3 (PPH3) in invasive lymph node-negative breast cancer patients less than 71 years of age

We validated and compared the prognostic value of the proliferation marker phosphohistone H3 (PPH3) with classical variables in 241 T(1-2)N(0)M(0) breast cancer patients less than 71 years old with long-term follow-up (median 117 months) and without adjuvant treatment. PPH3 was measured by automated digital image analysis. Thirty-seven patients (15%) developed distant metastases and 29 (12%) died. The previously established PPH3 prognostic threshold H3 <13 (n = 157; 65% of all cases) vs. >or=13 (n = 84; 35% of all cases) was the strongest prognostic threshold exceeding all other characteristics, with 10-year recurrence-free survival of distant metastases of 96 and 64%, respectively (P = < 0.0001, hazard ratio = 7.8, 95% confidence interval = 3.4-17.9). PPH3 is robust as it showed high inter-observer reproducibility and was prognostic over wide range of thresholds around 13 and is the strongest prognostic variable in invasive node-negative breast cancer patients less than 71 years old.

Phosphohistone H3 expression has much stronger prognostic value than classical prognosticators in invasive lymph node-negative breast cancer patients less than 55 years of age

The proliferation factor mitotic activity index is the strongest prognostic factor in early breast cancer, but it may lack reproducibility. We analyzed the prognostic value of phosphohistone H3, a marker of cells in late G(2) and M phase, measuring highly standardized immunohistochemical nuclear phosphohistone H3 expression by subjective counts and digital image analysis. Expression was compared with classical clinico-pathologic prognostic variables and the mitotic activity index in 119 node-negative invasive breast cancers in patients less than 55 years old treated with adjuvant systemic chemotherapy with long-term follow-up (median 168 months). Nineteen patients (16%) developed distant metastases and 16 (13%) died. Strong phosphohistone H3 expression occurred preferentially in the peripheral growing front; counts were highly reproducible between observers (R=0.92) and highly consistent with digital image analysis (R=0.96). Phosphohistone H3 correlated (P<0.05) with tumor diameter, estrogen receptor, carcinoma grade, and mitotic activity index. Phosphohistone H3 values were systematically (80%) higher than the mitotic activity index. Receiver-operating curve analysis objectively showed that phosphohistone H3 <13 (n=53; 45% of all cases) vs phosphohistone H3> or =13 (n=66; 55% of all cases) was the strongest prognostic threshold, with 20-year recurrence-free survival of distant metastases of 96 and 58%, respectively (P=0.0002, HR=9.6). Mitotic activity index was the second strongest prognostic variable (P=0.003, HR=3.9). In multivariate analysis, phosphohistone H3 <13 vs> or =13 exceeded the prognostic value of the mitotic activity index. None of the other classical prognostic factors examined offered prognostic value additional to phosphohistone H3. Phosphohistone H3 is by far the strongest prognostic variable in early invasive node-negative breast cancer patients less than 55 years old with long-term follow-up.