Anand D. Purushotham

Morbidity After Sentinel Lymph Node Biopsy in Primary Breast Cancer: Results From a Randomized Controlled Trial

PURPOSE Axillary lymph node dissection (ALND) as part of surgical treatment for patients with breast cancer is associated with significant morbidity. Sentinel lymph node biopsy (SLNB) is a newly developed method of staging the axilla and has the potential to avoid an ALND in lymph node-negative patients, thereby minimizing morbidity. The aim of this study was to investigate physical and psychological morbidity after SLNB in the treatment of early breast cancer in a randomized controlled trial. PATIENTS AND METHODS Between November 1999 and February 2003, 298 patients with early breast cancer (tumors 3 cm or less on ultrasound examination) who were clinically node negative were randomly allocated to undergo ALND (control group) or SLNB followed by ALND if subsequently found to be lymph node positive (study group). A detailed assessment of physical and psychological morbidity was performed during a 1-year period postoperatively. RESULTS A significant reduction in postoperative arm swelling, rate of seroma formation, numbness, loss of sensitivity to light touch and pinprick was observed in the study group. Although shoulder mobility was less impaired on average in the study group, this was significant only for abduction at 1 month and flexion at 3 months. Scores reflecting quality of life and psychological morbidity were significantly better in the study group in the immediate postoperative period, with fewer long-term differences. CONCLUSION SLNB in patients undergoing surgery for breast cancer results in a significant reduction in physical and psychological morbidity.

Terahertz pulsed spectroscopy of freshly excised human breast cancer

The complex refractive indices of freshly excised healthy breast tissue and breast cancers collected from 20 patients were measured in the range of 0.15 - 2.0 THz using a portable terahertz pulsed transmission spectrometer. Histology was performed to classify the tissue samples as healthy adipose tissue, healthy fibrous breast tissue, or breast cancers. The average complex refractive index was determined for each group and it was found that samples containing cancer had a higher refractive index and absorption coefficient. The terahertz properties of the tissues were also used to simulate the impulse response functions expected when imaging breast tissue in a reflection geometry as in terahertz pulsed imaging (TPI). Our results indicate that both TPS and TPI can be used to distinguish between healthy adipose breast tissue, healthy fibrous breast tissue and breast cancer due to the differences in the fundamental optical properties.

Alpha-6 integrin is necessary for the tumourigenicity of a stem cell-like subpopulation within the MCF7 breast cancer cell line

The identification of mammary epithelial stem cells raises the hypothesis that these cells may be crucial in the pathogenesis of breast cancer. To further support this, a highly tumourigenic sub‐population of cancer cells has recently been identified in primary and metastatic breast cancer samples. In this study, a sub‐population of cells displaying features normally attributed to stem cells was identified within the breast cancer cell line MCF‐7. This sub‐population is capable of growth in anchorage‐independent conditions as spherical organoids, displays resistance to proapoptotic agents and significantly greater tumourigenicity than its parental line, with as few as 1,000 cells able to form tumours in immunodeficient mice. Cells within this sub‐population can be enriched by serial passages in anchorage‐independence, and are characterized by over‐expression of the adhesion molecule α6‐integrin. Alpha‐6 integrin proves to be required for the growth and survival of these cells, as the knockdown of ITGA6 causes mammosphere‐derived cells to lose their ability to grow as mammospheres and abrogates their tumourigenicity in mice. These findings support the existence of a highly tumourigenic sub‐population in breast cancer cells. Furthermore, it shows α6‐integrin as a potential therapeutic target aimed at tumour‐generating subsets of breast cancer cells.

A novel model of dormancy for bone metastatic breast cancer cells

Mortality of patients with breast cancer is due overwhelmingly to metastatic spread of the disease. Although dissemination is an early event in breast cancer, extended periods of cancer cell dormancy can result in long latency of metastasis development. Deciphering the mechanisms underlying cancer cell dormancy and subsequent growth at the metastatic site would facilitate development of strategies to interfere with these processes. A challenge in this undertaking has been the lack of models for cancer cell dormancy. We have established novel experimental systems that model the bone microenvironment of the breast cancer metastatic niche. These systems are based on 3D cocultures of breast cancer cells with cell types predominant in bone marrow. We identified conditions in which cancer cells are dormant and conditions in which they proliferate. Dormant cancer cells were able to proliferate upon transfer into supportive microenvironment or upon manipulation of signaling pathways that control dormancy. These experimental systems will be instrumental for metastasis studies, particularly the study of cellular dormancy.

Lymph Node Status and Breast Cancer-related Lymphedema

Objective:This study examines the association between nodal positivity and risk of developing breast cancer-related lymphedema (BCRL) in patients who underwent axillary lymph node dissection (ALND). Summary Background Data:The pathophysiology of BCRL is poorly understood. It has been assumed that one of the factors predisposing to the development of BCRL is nodal positivity, although retrospective series have produced contradictory findings. As these studies have included treatment regimens known to cause BCRL, such as axillary radiotherapy, any relationship between nodal positivity and the development of BCRL remains speculative. Methods:A total of 212 patients who had undergone ALND for invasive breast cancer had arm volume measurements preoperatively, and at intervals postoperatively. No patient received axillary radiotherapy. Arm volumes were obtained by measuring serial arm circumferences every 4 cm up the arm and then calculated by using the formula for the volume of a truncated cone. Robust regression techniques were used to analyze the effects of node positivity, age, preoperative body mass index, and wound infection on arm volume excess. Results:In all, 64 of 212 (30%) patients were node positive. Contrary to previous assumptions, positive node status was significantly inversely associated with arm volume after adjusting for tumor size, time since operation, and allowing for correlated observations within subjects. Furthermore, the number of positive nodes also correlated inversely with arm volume. Conclusion:These results are counterintuitive to the conventional understanding of the pathophysiology of BCRL. A possible explanation is that patients who develop disease in axillary lymph nodes and subsequently undergo ALND have more time and ability to develop lymphatic collaterals, which may provide adequate lymphatic drainage following surgery, thereby reducing the risk of developing BCRL.

Aldehyde dehydrogenase and estrogen receptor define a hierarchy of cellular differentiation in the normal human mammary epithelium

IntroductionAlthough estrogen and progesterone play a key role in normal mammary development and in breast cancer, the potential for proliferation and lineage differentiation as well as origin of cells that express the estrogen receptor (ER) in normal breast epithelium are not known. Some evidence suggests that normal human mammary stem/progenitor cells are ER–, but the identity of these cells and the cellular hierarchy of breast epithelium are still subjects of controversy. It is likely that elucidation of these aspects will bring insight into the cellular origin of breast cancer subtypes.MethodsWe used fluorescence-activated cell sorting of primary human mammary epithelial cells along with in vitro and in vivo functional assays to examine the hierarchic relation between cells with aldehyde dehydrogenase enzymatic activity (ALDH+ cells) and ER+ cells in the normal human breast epithelium. We assessed the proliferation and lineage differentiation potential of these cells in vitro and in vivo. A gene reporter assay was used to separate live ER+ and ER– mammary epithelial cells. With shRNA-mediated knockdown, we investigated the role of ALDH isoforms in the functionality of mammary epithelial progenitor cells.ResultsWe describe a cellular hierarchy in the normal human mammary gland in which ER–/ALDH+ cells with functional properties of stem/progenitor cells generate ER+ progenitor cells, which in turn give rise to cells of luminal lineage. We show that the ALDH1A1 isoform, through its function in the retinoic acid metabolism, affects the proliferation and/or early differentiation of stem/progenitor cells and is important for branching morphogenesis.ConclusionsThis study presents direct evidence that ER+ cells are generated by ER–/ALDH+ stem/progenitor cells. We also show that ER+ cells are able to generate cell progeny of luminal lineage in vitro and in vivo. Loss of ALDH1A1 function impairs this process, as well as branching morphogenesis and clonogenicity in suspension culture. This latter effect is reversed by treatment with retinoic acid.

Axillary vein abnormalities contribute to development of lymphoedema after surgery for breast cancer.

The aetiology of breast cancer‐related lymphoedema (BCRL) is poorly understood and multifactorial. Previous work has suggested that acquired abnormalities of the axillary vein may contribute to arm swelling. This prospective study evaluated venous changes in patients with a new diagnosis of breast cancer who had surgery that included axillary lymph node clearance.

Lymphatic drainage pathways of the breast and the upper limb

ObjectiveTo determine how often the sentinel lymph node (SLN) draining the breast is the same node as the SLN draining the upper limb. A common SLN might increase the risk of upper limb breast cancer-related lymphoedema after SLN biopsy. MethodsPatients with invasive breast cancer, identified as being suitable for axillary lymph node dissection, were injected preoperatively with 40 MBq of technetium-99m (99mTc)-human polyclonal immunoglobulin G intradermally into the ipsilateral breast and 3 MBq of indium-111 (111In)-human polyclonal immunoglobulin G intradermally into the ipsilateral hand, or vice versa. Axillary lymph nodes were removed, separated and assayed in a well counter for 99mTc and 111In. ResultsFifteen patients entered the study. In 13 of 15 patients, the ‘hottest’ lymph node for 99mTc was separate from the ‘hottest’ lymph node for 111In. In two of 15 patients the ‘hottest’ lymph node for 99mTc was also the ‘hottest’ lymph node for 111In, suggesting a common drainage pathway from the ipsilateral breast and upper limb. ConclusionAlthough the majority of patients has different pathways of lymphatic drainage from the ipsilateral breast and upper limb, in a small minority of patients the drainage pathway is through a common SLN. Such patients may be at increased risk of developing upper limb breast cancer-related lymphoedema after SLN biopsy.

An intra-operative THz probe for use during the surgical removal of breast tumors

A portable intra-operative scanning terahertz (THz) probe has been developed for medical use by TeraView Ltd to aid surgeons in the removal of breast tumors by providing positive identification of diseased tissue in real-time. Initial ex vivo tests have been carried out using this system at Guypsilas Hospital, London, its ability to perform in a clinical environment has been tested by comparing THz data with histological diagnosis of localized areas of breast tissue from 27 patients as well as examination of sentinel node biopsies (SNB) of 37 patients. In this paper the system is described and findings of this initial study are discussed.

Growth Hormone Is Secreted by Normal Breast Epithelium upon Progesterone Stimulation and Increases Proliferation of Stem/Progenitor Cells

Summary Using in vitro and in vivo experimental systems and in situ analysis, we show that growth hormone (GH) is secreted locally by normal human mammary epithelial cells upon progesterone stimulation. GH increases proliferation of a subset of cells that express growth hormone receptor (GHR) and have functional properties of stem and early progenitor cells. In 72% of ductal carcinoma in situ lesions, an expansion of the cell population that expresses GHR was observed, suggesting that GH signaling may contribute to breast cancer development.