Giovanni Mazzarol

Biological and Molecular Heterogeneity of Breast Cancers Correlates with Their Cancer Stem Cell Content

Pathways that govern stem cell (SC) function are often subverted in cancer. Here, we report the isolation to near purity of human normal mammary SCs (hNMSCs), from cultured mammospheres, on the basis of their ability to retain the lipophilic dye PKH26 as a consequence of their quiescent nature. PKH26-positive cells possess all the characteristics of hNMSCs. The transcriptional profile of PKH26-positive cells (hNMSC signature) was able to predict biological and molecular features of breast cancers. By using markers of the hNMSC signature, we prospectively isolated SCs from the normal gland and from breast tumors. Poorly differentiated (G3) cancers displayed higher content of prospectively isolated cancer SCs (CSCs) than did well-differentiated (G1) cancers. By comparing G3 and G1 tumors in xenotransplantation experiments, we directly demonstrated that G3s are enriched in CSCs. Our data support the notion that the heterogeneous phenotypical and molecular traits of human breast cancers are a function of their CSC content.

Axillary dissection versus no axillary dissection in patients with sentinel-node micrometastases (IBCSG 23–01): a phase 3 randomised controlled trial

BACKGROUND For patients with breast cancer and metastases in the sentinel nodes, axillary dissection has been standard treatment. However, for patients with limited sentinel-node involvement, axillary dissection might be overtreatment. We designed IBCSG trial 23-01 to determine whether no axillary dissection was non-inferior to axillary dissection in patients with one or more micrometastatic (≤2 mm) sentinel nodes and tumour of maximum 5 cm. METHODS In this multicentre, randomised, non-inferiority, phase 3 trial, patients were eligible if they had clinically non-palpable axillary lymph node(s) and a primary tumour of 5 cm or less and who, after sentinel-node biopsy, had one or more micrometastatic (≤2 mm) sentinel lymph nodes with no extracapsular extension. Patients were randomly assigned (in a 1:1 ratio) to either undergo axillary dissection or not to undergo axillary dissection. Randomisation was stratified by centre and menopausal status. Treatment assignment was not masked. The primary endpoint was disease-free survival. Non-inferiority was defined as a hazard ratio (HR) of less than 1·25 for no axillary dissection versus axillary dissection. The analysis was by intention to treat. Per protocol, disease and survival information continues to be collected yearly. This trial is registered with ClinicalTrials.gov, NCT00072293. FINDINGS Between April 1, 2001, and Feb 28, 2010, 465 patients were randomly assigned to axillary dissection and 469 to no axillary dissection. After the exclusion of three patients, 464 patients were in the axillary dissection group and 467 patients were in the no axillary dissection group. After a median follow-up of 5·0 (IQR 3·6-7·3) years, we recorded 69 disease-free survival events in the axillary dissection group and 55 events in the no axillary dissection group. Breast-cancer-related events were recorded in 48 patients in the axillary dissection group and 47 in the no axillary dissection group (ten local recurrences in the axillary dissection group and eight in the no axillary dissection group; three and nine contralateral breast cancers; one and five [corrected] regional recurrences; and 34 and 25 distant relapses). Other non-breast cancer events were recorded in 21 patients in the axillary dissection group and eight in the no axillary dissection group (20 and six second non-breast malignancies; and one and two deaths not due to a cancer event). 5-year disease-free survival was 87·8% (95% CI 84·4-91·2) in the group without axillary dissection and 84·4% (80·7-88·1) in the group with axillary dissection (log-rank p=0·16; HR for no axillary dissection vs axillary dissection was 0·78, 95% CI 0·55-1·11, non-inferiority p=0·0042). Patients with reported long-term surgical events (grade 3-4) included one sensory neuropathy (grade 3), three lymphoedema (two grade 3 and one grade 4), and three motor neuropathy (grade 3), all in the group that underwent axillary dissection, and one grade 3 motor neuropathy in the group without axillary dissection. One serious adverse event was reported, a postoperative infection in the axilla in the group with axillary dissection. INTERPRETATION Axillary dissection could be avoided in patients with early breast cancer and limited sentinel-node involvement, thus eliminating complications of axillary surgery with no adverse effect on survival. FUNDING None.

Sentinel-lymph-node biopsy as a staging procedure in breast cancer: update of a randomised controlled study

BACKGROUND In women with breast cancer, sentinel-lymph-node biopsy (SLNB) provides information that allows surgeons to avoid axillary-lymph-node dissection (ALND) if the SLN does not have metastasis, and has a favourable effect on quality of life. Results of our previous trial showed that SLNB accurately screens the ALN for metastasis in breast cancers of diameter 2 mm or less. We aimed to update this trial with results from longer follow-up. METHODS Women with breast tumours of diameter 2 cm or less were randomly assigned after breast-conserving surgery either to SLNB and total ALND (ALND group), or to SLNB followed by ALND only if the SLN was involved (SLN group). Analysis was restricted to patients whose tumour characteristics met eligibility criteria after treatment. The main endpoints were the number of axillary metastases in women in the SLN group with negative SLNs, staging power of SLNB, and disease-free and overall survival. FINDINGS Of the 257 patients in the ALND group, 83 (32%) had a positive SLN and 174 (68%) had a negative SLN; eight of those with negative SLNs were found to have false-negative SLNs. Of the 259 patients in the SLN group, 92 (36%) had a positive SLN, and 167 (65%) had a negative SLN. One case of overt clinical axillary metastasis was seen in the follow-up of the 167 women in the SLN group who did not receive ALND (ie, one false-negative). After a median follow-up of 79 months (range 15-97), 34 events associated with breast cancer occurred: 18 in the ALND group, and 16 in the SLN group (log-rank p=0.6). The overall 5-year survival of all patients was 96.4% (95% CI 94.1-98.7) in the ALND group and 98.4% (96.9-100) in the SLN group (log-rank p=0.1). INTERPRETATION SLNB can allow total ALND to be avoided in patients with negative SLNs, while reducing postoperative morbidity and the costs of hospital stay. The finding that only one overt axillary metastasis occurred during follow-up of patients who did not receive ALND (whereas eight cases were expected) could be explained by various hypotheses, including those from cancer-stem-cell research.

Sentinel lymph node biopsy in breast cancer: ten-year results of a randomized controlled study.

Objective:Sentinel node biopsy (SNB) is widely used to stage the axilla in breast cancer. We present 10-year follow-up of our single-institute trial designed to compare outcomes in patients who received no axillary dissection if the sentinel node was negative, with patients who received complete axillary dissection. Methods:From March 1998 to December 1999, 516 patients with primary breast cancer up to 2 cm in pathologic diameter were randomized either to SNB plus complete axillary dissection (AD arm) or to SNB with axillary dissection only if the sentinel node contained metastases (SN arm). Results:The 2 arms were well-balanced for number of sentinel nodes found, proportion of positive sentinel nodes, and all other tumor and patient characteristics. About 8 patients in the AD arm had false-negative SNs on histologic analysis: a similar number (8, 95% CI: 3–15) of patients with axillary involvement was expected in SN arm patients who did not receive axillary dissection; but only 2 cases of overt axillary metastasis occurred. There were 23 breast cancer-related events in the SN arm and 26 in the AD arm (log-rank, P = 0.52), while overall survival was greater in the SN arm (log-rank, P = 0.15). Conclusions:Preservation of healthy lymph nodes may have beneficial consequences. Axillary dissection should not be performed in breast cancer patients without first examining the sentinel node.

Alterations of the Notch pathway in lung cancer

Notch signaling regulates cell specification and homeostasis of stem cell compartments, and it is counteracted by the cell fate determinant Numb. Both Numb and Notch have been implicated in human tumors. Here, we show that Notch signaling is altered in approximately one third of non–small-cell lung carcinomas (NSCLCs), which are the leading cause of cancer-related deaths: in ≈30% of NSCLCs, loss of Numb expression leads to increased Notch activity, while in a smaller fraction of cases (around 10%), gain-of-function mutations of the NOTCH-1 gene are present. Activation of Notch correlates with poor clinical outcomes in NSCLC patients without TP53 mutations. Finally, primary epithelial cell cultures, derived from NSCLC harboring constitutive activation of the Notch pathway, are selectively killed by inhibitors of Notch (γ-secretase inhibitors), showing that the proliferative advantage of these tumors is dependent upon Notch signaling. Our results show that the deregulation of the Notch pathway is a relatively frequent event in NSCLCs and suggest that it might represent a possible target for molecular therapies in these tumors.

Predicting the Risk for Additional Axillary Metastases in Patients With Breast Carcinoma and Positive Sentinel Lymph Node Biopsy

Objective:To assess whether the risk for nonsentinel node metastases may be predicted, thus sparing a subgroup of patients with breast carcinoma and a positive sentinel lymph node (SLN) biopsy completion axillary lymph node dissection (ALND). Summary Background Data:The SLN is the only involved axillary lymph node in the majority of the patients undergoing ALND for a positive SLN biopsy. A model to predict the status of nonsentinel axillary lymph nodes could help tailor surgical therapy to those patients most likely to benefit from completion ALND. Methods:All the axillary sentinel and nonsentinel lymph nodes of 1228 patients were reviewed histologically and reclassified according to the current TNM classification of malignant tumors as bearing isolated tumor cells only, micrometastases, or (macro)metastases. The prevalence of metastases in nonsentinel lymph nodes was correlated to the type of SLN involvement and the size of the metastasis, the number of affected SLNs, and the prospectively collected clinicopathologic variables of the primary tumors. Results:In multivariate analysis, further axillary involvement was significantly associated with the type and size of SLN metastases, the number of affected SLNs, and the occurrence of peritumoral vascular invasion in the primary tumor. A predictive model based on the characteristics most strongly associated with nonsentinel node metastases was able to identify subgroups of patients at significantly different risk for further axillary involvement. Conclusions:Patients with the most favorable combination of predictive factors still have no less than 13% risk for nonsentinel lymph node metastases and should be offered completion ALND outside of clinical trials of SLN biopsy without back-up axillary clearing.

Size of Breast Cancer Metastases in Axillary Lymph Nodes: Clinical Relevance of Minimal Lymph Node Involvement

BACKGROUND Overt ipsilateral axillary lymph node metastases of breast cancer are the most significant prognostic indicators for women who have undergone surgery, yet the clinical relevance of minimal involvement (isolated tumor cells and micrometastases) of these nodes is uncertain. PATIENTS AND METHODS We evaluated biologic features, adjuvant treatment recommendations, and prognosis for 1,959 consecutive patients with pT1-3, pN0, minimal lymph node involvement (pN1mi or pN0i+), or pN1a (single positive node) and M0, who were operated on and counseled for medical therapy from April 1997 to December 2000. RESULTS Patients with pN1a and pN1mi/pN0i+, when compared with patients with pN0 disease, were more often prescribed anthracycline-containing chemotherapy (39.1% v 33.2% v 6.1%, respectively; P < .0001) and were less likely to receive endocrine therapy alone (9.8% v 19.4% v 41.9%, respectively; P < .0001). At the multivariate analysis, a statistically significant difference in disease-free survival (DFS) and in the risk of distant metastases was observed for patients with pN1a versus pN0 disease (hazard ratio [HR] = 2.04; 95% CI, 1.46 to 2.86; P < .0001 for DFS; HR = 2.32; 95% CI, 1.42 to 3.80; P = .0007 for distant metastases) and for patients with pN1mi/pN0i+ versus pN0 disease (HR = 1.58; 95% CI, 1.01 to 2.47; P = .047 for DFS; HR = 1.94; 95% CI, 1.04 to 3.64; P = .037 for distant metastases). CONCLUSION Even minimal involvement of a single axillary node in breast cancer significantly correlates with worse prognosis compared with no axillary node involvement. Further studies are required before widespread modification of clinical practice.

Reciprocal repression between P53 and TCTP

Screening for genes that reprogram cancer cells for the tumor reversion switch identified TCTP (encoding translationally controlled tumor protein) as a crucial regulator of apoptosis. Here we report a negative feedback loop between P53 and TCTP. TCTP promotes P53 degradation by competing with NUMB for binding to P53-MDM2–containing complexes. TCTP inhibits MDM2 auto-ubiquitination and promotes MDM2-mediated ubiquitination and degradation of P53. Notably, Tctp haploinsufficient mice are sensitized to P53-dependent apoptosis. In addition, P53 directly represses TCTP transcription. In 508 breast cancers, high-TCTP status associates with poorly differentiated, aggressive G3-grade tumors, predicting poor prognosis (P < 0.0005). Tctp knockdown in primary mammary tumor cells from ErbB2 transgenic mice results in increased P53 expression and a decreased number of stem-like cancer cells. The pharmacological compounds sertraline and thioridazine increase the amount of P53 by neutralizing TCTPs action on the MDM2-P53 axis. This study links TCTP and P53 in a previously unidentified regulatory circuitry that may underlie the relevance of TCTP in cancer.

Comparative evaluation of an extensive histopathologic examination and a real-time reverse-transcription-polymerase chain reaction assay for mammaglobin and cytokeratin 19 on axillary sentinel lymph nodes of breast carcinoma patients.

Objective:To assess the accuracy of a commercially available real-time reverse-transcription-polymerase chain reaction assay for mammaglobin and cytokeratin 19 mRNAs [GeneSearch Breast Lymph Node (BLN) Assay, Veridex LLC, Warren, NJ] in the detection of axillary sentinel lymph nodes (SLNs) metastases in patients with breast carcinoma. Summary Background Data:Because of the lack of standardized and widely accepted protocols for a truly accurate histopathologic examination of SLN, the relative merits of alternative assays based on the identification of tumor specific mRNA markers deserve further assessment. Methods:A prospective series of 293 consecutive SLNs from 293 patients was evaluated. The BLN assay results were compared with those of an extensive histopathologic examination of the entire SLNs performed on serial frozen sections cut at 40 to 50 &mgr;m intervals. Results:The BLN assay correctly identified 51 of 52 macrometastatic and 5 of 20 micrometastatic SLNs, with a sensitivity of 98.1% to detect metastases larger than 2 mm, 94.7% for metastases larger than 1 mm, and 77.8% for metastases larger than 0.2 mm. The overall concordance with histopathology was 90.8%, with specificity of 95.0%, positive predictive value of 83.6%, and negative predictive value of 92.9%. When the results were evaluated according to the occurrence of additional metastases to non-SLN in patients with histologically positive SLNs, the assay was positive in 33 (91.7%) of the 36 patients with additional metastases and in 22 (66.6%) of the 33 patients without further echelon involvement. Conclusions:The sensitivity of the reverse-transcription -polymerase chain reaction assay is comparable to that of the histopathologic examination of the entire SLN by serial sectioning at 1.5 to 2 mm.

Response to primary chemotherapy in breast cancer patients with tumors not expressing estrogen and progesterone receptors

BACKGROUND We recently demonstrated that in premenopausal patients with estrogen receptors (ER)-absent tumors, early initiation of systemic chemotherapy after primary surgery might improve outcome. These data indicate a different responsiveness to chemotherapy for tumors not expressing hormone receptors. To test this hypothesis we evaluated the responsiveness to preoperative chemotherapy in patients with ER and progesterone receptors (PgR)-absent tumors. PATIENTS AND METHODS Patients with biopsy-proven T2-T3, N0-2 breast cancer treated at a single institution from January 1995 to August 1999 with preoperative chemotherapy were retrospectively evaluated. ER and PgR were determined immunohistochemically and classified for this purpose as absent (0% of the cells positive) or positive (> or = 1% of the cells). RESULTS On 117 evaluable patients 72 had an objective response (61%). A significant difference in response was observed for patients with ER and PgR absent compared with those with ER and/or PgR-positive tumors (82% vs. 57%, P = 0.03 Fisherss exact test). Pathological complete remission rates were also significantly different in the two groups (23% vs. 7%, respectively; P = 0.04). CONCLUSIONS The different degree of response according to hormone receptors expression supports the hypothesis that tumors not expressing both ER and PgR might represent a different clinical entity in terms of chemotherapy responsiveness.