Differential assessment of angiogenic activity and of vascular survival ability (VSA) in breast cancer

Recent reports provide evidence that some growth factors behave as inhibitors of the apoptosis of the endothelial cells, bringing forward the concept of vascular survival as a post-angiogenesis process. At least two different vasculature development processes occur within a tumor: the angiogenic (formation of new vessels) and the vascular survival pathway, which is devoted to the preservation of the newly-formed vessels in layers that lose contact with the adjacent normal tissue. We developed a method to assess these processes in tissue samples. We noted that differences among tumors may exist not only in the tumor angiogenic activity (TAA) but also in the vascular survival ability (VSA). One third of the highly angiogenic breast cancer cases examined had a poor ability to maintain high vessel density in inner tumor areas. Both parameters are independently related to prognosis, while VSA was directly related to tumor dimensions and node involvement. Patients with high TAA and VSA had a particularly poor prognosis. It is suggested that although cancer angiogenic activity is important for the local invasion and dissemination into vessels and lymphatics, the VSA may be important for the effective formation of viable tumor foci in lymph nodes or distant organs. Recognition and quantification of the vascular survival ability in human tumors may significantly improve the prognostic value of the assessment of tumor vasculature, and may help to stratify patients for clinical trials with novel anti-angiogenic or angiotoxic drugs. Elucidation of the pathways may provide additional targets for antiangiogenic therapy. This revised version was published online in July 2006 with corrections to the Cover Date.     

'Invading edge vs. inner' (edvin) patterns of vascularization: an interplay between angiogenic and vascular survival factors defines the clinical behaviour of non-small cell lung cancer

Neo-angiogenesis during neoplastic growth involves endothelial mitogenic and migration stimuli produced by cancer or tumour stromal cells. Although this active angiogenesis takes place in the tumour periphery, the process of vessel growth and survival in inner areas and its clinical role remain largely unexplored. The present study compared the microvessel score (MS) as well as the single endothelial cell score (ECS) in the invading edge and in inner areas of non-small cell lung carcinomas (NSCLCs). Three different patterns of vascular growth were distinguished: the edvin (edge vs. inner) type 1, where a low MS was observed in both peripheral and inner tumour areas; the edvin type 2, where a high MS was noted in the invading front but a low MS in inner areas; and the edvin type 3, where both peripheral and inner tumour areas had a high MS. The ECS was high in the invading edge in edvin type 2 and 3 cases and was sharply decreased in both types in inner areas, suggesting that endothelial cell migration is unlikely to contribute to the angiogenic process in areas away from the tumour front. Expression of the vascular endothelial growth factor (VEGF) and of thymidine phosphorylase (TP) was associated with a high MS in the invading edge. VEGF was associated with a high MS in inner areas (edvin 3), while TP expression was associated with edvin type 2, showing that VEGF (and not TP) contributes to the preservation of the inner vasculature. Both edvin type 2 and 3 cases showed an increased incidence of node metastasis, but edvin type 3 cases had a poorer prognosis, even in the N1-stage group. The present study suggests that tumour factors regulating angiogenesis and vascular survival are not identical. A possible method is reported to quantify these two parameters by comparing the MS in the invading edge and inner areas (edvin types). This observation may contribute to the evaluation of the effectiveness of different therapeutic approaches, namely vascular targeting vs. anti-angiogenesis.     

Tumour angiogenesis: vascular growth and survival

Angiogenesis starts at the edge of a malignant epithelial tumour concurrently with tumour cell invasion and stromatogenesis, i.e. the formation of specific connective tissue stroma amenable to easy penetration by endothelial and tumour cells. However, as the tumour continues its growth, the edge becomes the inner tumour area, and a new invading tumour front is formed by the multiplying malignant cells which outflank the initial edge. This process, which repeats itself again and again, forms the "relay race" model of tumour vascular growth and regression. At the heart of the tumour unfavourable environmental conditions prevail -- hypoxia, acidity, lack of nutrients, failure of waste removal, and apoptosis rather than proliferation. Blood vessels and tumour cells are greatly decreased, but do not vanish, as tumour cells are shifting to anaerobic glycolysis, and blood vessels are turning into anti-apoptotic pathways -- vascular survival ability (VSA). Thus, assessing vascular density (VD) by simply counting "hot spots" at the edge of a tumour, where conditions are most favourable, is futile; it may reflect tumour angiogenic activity (TAA), but is not representative of genuine tumour vasculature. By combining vessel counts at the invading tumour front with those of the inner tumour areas a complete picture of tumour VD can be achieved. The thus formed four patterns of vascularization, designated as "edvin" (edge vsinner tumour area), are: edvin 1: low TAA/low VSA; edvin 4: high TAA/high VSA; edvin 2: low TAA/high VSA; and edvin 3: high TAA/low VSA. It is expected that this scheme will prove useful in the field of chemoradiotherapy and anti-angiogenic treatment.     

c-erbB-2 related aggressiveness in breast cancer is hypoxia inducible factor-1alpha dependent.

c-erbB-2-positive breast carcinomas are highly aggressive tumors. In vitro data on breast cell lines showed that c-erbB-2 enhanced translational efficiency of hypoxia inducible factor-1alpha (HIF1alpha) production (Laughner et al., Mol Cell Biol 2001;21:3995-4005). We investigated the clinical correlate of this observation to assess whether c-erbB-2 expression was related to HIF1alpha expression, angiogenesis, and prognosis. A series of 180 breast carcinomas of known c-erbB-2 status (90 c-erbB-2-positive and 90 c-erbB-2-negative carcinomas) were stained immunohistochemically for HIF1alpha and CD31 endothelial cell antigen. c-erbB-2 positivity was clearly related to HIF1alpha protein expression and high angiogenesis. However, prognosis was decreased only in cases with simultaneous c-erbB-2 and HIF1alpha expression. If activation of c-erbB-2 in humans results in overexpression of HIF1alpha independently of conditions of hypoxia, as occur in experimental studies, this interaction may represent a main pathway conferring clinical aggressiveness to c-erbB-2-positive breast tumors.     

Intrathoracic papillary thyroid carcinoma from occult primary disease

A 42-year-old woman undertook a chest radiograph for a routine evaluation prior to surgery for pelvic endometrioma, which revealed a right paratracheal mass slightly displacing the trachea to the left. CT of the thorax disclosed a well demarcated, heterogeneous, lobular, right paratracheal mass, bearing punctate, coarse, and curvilinear calcifications. MRI further revealed two components within the lesion: a larger, cystic, exhibiting thin septations, and a solid component at the lower part exhibiting strong enhancement. No continuity of the mass with the thyroid gland was demonstrated, which had normal size and no focal lesion. Histological examination of the resected mass disclosed lymph node tissue infiltrated by papillary thyroid carcinoma; subsequent total thyroidectomy revealed small foci of papillary carcinoma within both lobes of the thyroid gland. Ablative dose I-131 was administered and the patient was put on daily thyroid supplements.     

Demystifying endometrial hyperplasia

The endometrial hyperplasias form a spectrum of proliferative lesions, not all of which conform to conventional definition of hyperplasia. For whilst most hyperplastic lesions are composed of cells normally occurring in the late proliferative phase endometrium, there are those few which consist of genuine atypical cells. Lesions of this type, so-called “atypical endometrial hyperplasias”, tend to merge imperceptibly with well differentiated endometrioid adenocarcinomas, giving rise to major challenges: First and foremost, what are the very essential criteria that should be met before diagnosing such a lesion? And what are the very least that should be insisted upon for diagnosing malignancy once an atypical endometrial hyperplasia has been established? What is its true nature and how should ideally be classified? Other less conflicting, but equally interesting, aspects of endometrial hyperplasia which are covered in this account include the conventional hyperplasias, i.e. those lacking cytological atypia, and the overall incidence, risk factors and treatment of the disease. It is worth noting that “pure” stromal cell proliferations are, in itself, not necessarily neoplastic, for many take the form of endometrial stromal hyperplasia.     

BNIP3 expression in follicular lymphoma

AIMS: To investigate the role of BNIP3, a 19-kDa interacting protein of the Bcl-2 family, alongside Bcl-2 in follicular lymphoma in comparison with reactive lymphoid hyperplasia. The results were compared with those from p53 and caspase-3 (apoptotic markers) and Ki67 (proliferation marker). METHODS AND RESULTS: Immunohistochemistry using monoclonal antibodies showed BNIP3 to be strongly expressed in most follicular lymphomas but to be weak to negative in all of the reactive cases. There was also an inverse relationship with Bcl-2 expression. There was no correlation of BNIP3 immunoreactivity with proliferation and caspase and p53 were virtually negative in all follicular lymphomas and reactive lymphoid cases. CONCLUSIONS: BNIP3 is strongly expressed in most follicular lymphomas, especially those that are Bcl-2 negative. BNIP3 may serve as a marker of more aggressive behaviour in follicular lymphoma and be useful diagnostically in the distinction from reactive lymphadenitis.     

Patterns of autophagy in urothelial cell carcinomas—the significance of “stone-like” structures (SLS) in transurethral resection biopsies

ObjectivesTo investigate the microtubule-associated protein LC3A, presumed to reflect autophagic activity, in urothelial cell carcinomas (UCC) for its relevance with muscle invasion in transurethral resection (TUR) biopsies. The LC3A antibody is specific for identifying the autophagy-related protein Atg8 and, hence, autophagy—a self-degradation mechanism by which cells recycle their own cytoplasmic constituents, providing with additional energy the rapidly proliferating cells.MethodsThe study comprised 210 TUR specimens of UCC of the urinary bladder: 70 low-grade non-muscle-invasive (NMI, group A), 70 high-grade NMI (group B), and 70 high-grade muscle invasive tumors (group C). These, together with 40 controls, were stained for Atg8/LC3 using an automated immunohistochemical technique.ResultsThe LC3A was detected as diffuse cytoplasmic staining, and as dense, spheroidal, “stone-like” structures (SLS) of variable size (1.2–12.0 μm in diameter), typically enclosed within cytoplasmic vacuoles. The LC3A reactivity, whether expressed in the form of SLS or as diffuse cytoplasmic staining, was higher in high-grade UCC than in low-grade disease and, more importantly, it was associated with muscle invasion. The median number of SLS per optical field, per section was 17.0, 19.0, and 37.0 for groups A, B, and C, respectively (A, B vs. C P < 178> 0.0001; A vs. B P = 0.27). The median SLS diameter was 4.9, 5.3, and 9.3 μm for groups A, B, and C respectively (A, B, vs. C P < 0.0001; A vs. B P = 0.03).ConclusionIt appears that the LC3A protein is closely connected with muscle invasion, but whether this finding is of clinical value in TUR specimens lacking muscularis propria remains to be proven.     

Malignant haemangiopericytoma of the knee joint: MR findings

The imaging findings of intra-articular haemangiopericytomas have not been described previously. We report on a 35-year-old man with a primary malignant haemangiopericytoma of the left knee joint. MRI demonstrated joint effusion and a heterogeneous mass with haemorrhagic components and multiple peripheral serpentine signal voids, suggesting the presence of vascular channels. Multiple pulmonary metastases were seen on chest CT. These imaging findings, although not pathognomonic, might be useful in suggesting the diagnosis of intra-articular haemangiopericytoma.