Hypoxia in breast cancer: role of blood flow, oxygen diffusion distances, and anemia in the development of oxygen depletion

Heterogeneously distributed hypoxic areas are a characteristic property of locally advanced breast cancers. Hypoxia results from an imbalance between the supply and consumption of oxygen (O2). Major pathogenetic mechanisms for the emergence of hypoxia are (i) structural and functional abnormalities in the tumor microvasculature, (ii) an adverse diffusion geometry, and (iii) tumor-related and therapy-induced anemia leading to a reduced O2 transport capacity of the blood. There is pronounced intertumor variability in the extent of hypoxia, which is independent of clinical size, stage, histology and grade. Hypoxia is intensified in anemic patients, especially in tumor (areas) with low perfusion rates. Tumor hypoxia is a therapeutic problem since it makes solid tumors resistant to sparsely ionizing radiation, some forms of chemotherapy, and photodynamic therapy. However, besides more direct mechanisms involved in the development of therapeutic resistance, there are, in addition, indirect machineries that can cause barriers to therapies. These include hypoxia-mediated alterations in gene expression, proteomic and genomic changes, and clonal selection. These in turn can drive subsequent events that are known to further increase resistance to therapy in addition to critically affecting long-term prognosis.

Connective Tissue Growth Factor–Specific Monoclonal Antibody Therapy Inhibits Pancreatic Tumor Growth and Metastasis

Pancreatic cancer is highly aggressive and refractory to most existing therapies. Past studies have shown that connective tissue growth factor (CTGF) expression is elevated in human pancreatic adenocarcinomas and some pancreatic cancer cell lines. To address whether and how CTGF influences tumor growth, we generated pancreatic tumor cell lines that overexpress different levels of human CTGF. The effect of CTGF overexpression on cell proliferation was measured in vitro in monolayer culture, suspension culture, or soft agar, and in vivo in tumor xenografts. Although there was no effect of CTGF expression on proliferation in two-dimensional cultures, anchorage-independent growth (AIG) was enhanced. The capacity of CTGF to enhance AIG in vitro was linked to enhanced pancreatic tumor growth in vivo when these cells were implanted s.c. in nude mice. Administration of a neutralizing CTGF-specific monoclonal antibody, FG-3019, had no effect on monolayer cell proliferation, but blocked AIG in soft agar. Consistent with this observation, anti-CTGF treatment of mice bearing established CTGF-expressing tumors abrogated CTGF-dependent tumor growth and inhibited lymph node metastases without any toxicity observed in normal tissue. Together, these studies implicate CTGF as a new target in pancreatic cancer and suggest that inhibition of CTGF with a human monoclonal antibody may control primary and metastatic tumor growth.

Carbonic anhydrase IX expression and tumor oxygenation status do not correlate at the microregional level in locally advanced cancers of the uterine cervix

PURPOSE

Carbonic anhydrase IX (CA IX) can be induced by hypoxia in vitro and shows an immunohistochemical expression pattern that is predominantly found in perinecrotic tumor areas and correlates with exogenous markers of hypoxia, such as pimonidazole. CA IX might therefore serve as an endogenous marker of tumor hypoxia, although comparisons of CA IX immunostaining with direct oxygenation measurements using pO2 microsensors have thus far yielded contradictory results.

EXPERIMENTAL DESIGN

Because tumor heterogeneity may be among the factors responsible for the discrepancy between the two methods, CA IX expression in tissue samples originating from oxygen microelectrode tracks of locally advanced cervical cancers was assessed in this study. Seventy-seven biopsy specimens were analyzed immunohistochemically using an anti-CA IX rabbit polyclonal antibody and semiquantitative scoring.

RESULTS

CA IX expression showed no correlation with the oxygenation variables median pO2 and hypoxic fraction 2.5, 5, or 10. Cases with higher International Federation of Gynecology and Obstetrics stages (IIb-IVa) exhibited stronger expression of CA IX (P = 0.035) and CA IX expression tended to be more prevalent in node-positive patients (P = 0.051).

CONCLUSIONS

These data indicate that CA IX cannot be recommended as a substitute for oxygen microelectrode measurements. That the expression of CA IX does not correlate with the oxygenation status may be due to the degree to which other factors, such as nutrient (e.g., glucose) deficiency or the action of oncogenic mutations, can modulate the in vivo expression of this protein, rendering a strict association with tumor hypoxia too unreliable for clinical use.

Impact of Hemoglobin Levels on Tumor Oxygenation: the Higher, the Better?

BACKGROUND AND PURPOSE

Tumor hypoxia has been linked to tumor progression, the development of treatment resistance, and thus poor prognosis. Since anemia is a major factor causing tumor hypoxia, the association between blood hemoglobin concentration (cHb) and tumor oxygenation status has been examined.

PATIENTS AND METHODS

Published data on the relationship between pretreatment cHb values and tumor oxygenation (in terms of median pO(2) values, hypoxic fractions) have been summarized. Pretreatment O(2) tension measurements were performed in histologically proven experimental tumors, human breast cancers, squamous cell carcinomas of the head and neck, and cancers of the uterine cervix and of the vulva. In order to allow for a comparison between solid tumors and normal tissues, pO(2) measurements were also performed in healthy tissue in anemic and nonanemic patients. cHb was determined at the time of the pO(2) measurements.

RESULTS

Based on current information from experimental and clinical studies there is increasing evidence that anemia is associated with a detrimental tumor oxygenation status. Increasing cHb values are correlated with significantly higher pO(2) values and lower hypoxic fractions. Maximum tumor oxygenation in squamous cell carcinomas is observed at normal (gender-specific) cHb values (approximately 14 g/dl in women and approximately 15 g/dl in men). Above this "optimal" Hb range, the oxygenation status tends to worsen again. In anemic patients, tumor oxygenation is compromised due to a decreased O(2) transport capacity of the blood. At the upper edge of the Hb scale, a substantial increase in the blood's viscous resistance to flow in "chaotic" tumor microvessels is thought to be mainly responsible for the observed restriction of O(2) supply.

CONCLUSION

Review of relevant clinical data suggests that a maximum oxygenation status in solid tumors is to be expected in the range 12 g/dl < cHb < 14 g/dl for women and 13 g/dl < cHb < 15 g/dl for men. Considering the "optimal" cHb range with regard to tumor oxygenation, the concept of "the higher, the better" is therefore no longer valid. This finding has potentially far-reaching implications in the clinical setting (e. g., inappropriate erythropoietin treatment of nonanemic tumor patients).

Placental localization and expression of the cell death factors BNip3 and Nix in preeclampsia, intrauterine growth retardation and HELLP syndrome

OBJECTIVE

BNip3 and its homologue Nix are pro-apoptotic factors of the Bcl-2-family and are expressed in malignant tumors. In vitro, this expression was shown to be mediated by hypoxia. Recently, it has been shown that placental hypoxia as well as apoptosis are pathogenetic factors for pregnancy-induced hypertensive diseases and intrauterine growth retardation (IUGR). The aim of the study was to analyze placental expression of BNip3 and Nix in pregnancies complicated by preeclampsia, hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome and IUGR.

MATERIAL AND METHODS

Placental tissue was sampled from 10 pregnancies each with preeclampsia, HELLP syndrome, IUGR and gestational age-matched controls. The placental expression of BNip3/Nix has been investigated with immunohistochemistry by the use of specific human BNip3/Nix antibodies.

RESULTS

In cytotrophoblastic cells, the BNip3 expression was strong in the control placentas, but only mediate in the placentas from pregnancies with preeclampsia, IUGR or HELLP syndrome. The intensity of the Nix staining showed a similar pattern. In the syncytiotrophoblast, there was a weak BNip3 staining observable in the control as well as IUGR samples, whereas BNip3 was undetectable in preeclamptic placentas or those with HELLP syndrome. For Nix, only in the preeclampsia a weak staining was detectable, whereas all other probes were negative.

CONCLUSIONS

Our study shows for the first time that the pro-apoptotic proteins BNip3 and Nix are expressed in the human placenta. Pregnancies with placental dysfunction and hypertensive pregnancy disorders with different clinical manifestations are characterized by a significantly decreased expression of BNip3 and Nix. These results suggest that the hypothesis of generally increased placental apoptosis in pregnancy-induced hypertensive disorders caused by disturbed trophoblast invasion has to be partly reconsidered.

Oxygenation status of primary and recurrent squamous cell carcinomas of the vulva

INTRODUCTION

Cancers of the vulva are relatively rare and, therefore, little is known about the pathophysiological role of tumor oxygenation in this entity.

METHODS

Data are presented on the oxygenation status of primary (n = 15) and recurrent (n = 19) cancers of the vulva, as measured by the Eppendorf pO2 histography system.

RESULTS

Contrary to other tumor entities, no significant differences in the oxygenation status between primary (median pO2 = 13 mmHg; hypoxic fraction < or = 5 mmHg = 37%) and recurrent (median pO2 = 11 mmHg; hypoxic fraction < or = 5 mmHg = 45%) tumors were found. Oxygenation was significantly lower in cancers of the vulva than in the subcutis. Anemic patients had significantly poorer tumor oxygenation compared with patients whose cHb values were within the normal range (p = 0.02).

CONCLUSIONS

The oxygenation of vulvar cancers is similar to other tumor entities, but does not show more severe hypoxia in recurrent cases. Anemia is associated with a poorer oxygenation status in vulvar cancers, whereas in the normal tissue no impact of cHb values on the median pO2 was observed.

Clonal history of papillomavirus-induced dysplasia in the female lower genital tract

BACKGROUND

Dysplastic lesions of the vagina or the vulva often occur in women who have a previous history of cervical dysplasia. Most lesions in the female lower genital tract are induced by infections with high-risk oncogenic human papillomaviruses (HR-HPVs), including HPV16 and HPV18. HR-HPV genomes frequently integrate into host cell chromosomes at random sites. We analyzed viral integration sites in multiple metachronous lesions of the lower genital tract from women previously treated for HR-HPV-positive cervical dysplasia or cancer to determine whether the metachronous lesions emerged from a single common preexisting dysplastic cell clone or as consequence of independent HR-HPV infection events in the female lower genital tract.

METHODS

From among 1500 patients with anogenital lesions, seven patients with high-grade vaginal or vulvar lesions and with a previous history of cervical disease (five with prior high-grade cervical dysplasia and two with a history of cervical cancer) were included in this study. Integration sites of HPV16 or HPV18 in vaginal or vulvar lesions were mapped by an adaptor ligation polymerase chain reaction (PCR) method. The sequence information was used to design an integrate-specific PCR assay that was applied to DNA extracted from archival paraffin-embedded material derived from biopsy samples of cervical lesions.

RESULTS

Identical HPV DNA integration loci were found in vaginal or vulvar and cervical samples of all lesions available for four of the five patients with a prior history of high-grade cervical dysplasia and for both patients with a history of cervical cancer.

CONCLUSIONS

These data indicate that high-grade dysplastic lesions in the female lower genital tract may emerge primarily as monoclonal lesions from a transformed cell population derived from the uterine cervix.

[Topographical anatomy of the female pelvis in ultrasound]

AIM

Achieving a high quality gynaecological ultrasound examination requires thorough knowledge of topographic anatomy. To date, there are no guidelines for a standardised course of the examination. The goal of the study was to define exact planes by means of cross-sectional anatomy and then to standardise the gynaecological ultrasound examination with the transabdominal, introital and transvaginal technique.

METHOD

We developed a software tool based on IDL (Interactive Data Language) for the female data set of the Visible Human Project which generates free determinable planes in the volume. The organs of the female pelvis were divided into landmark- and target structures according to the ultrasonic visibility and the variability of the position, shape and structure. From this, a course for the gynaecological ultrasound examination was created and verified on 65 patients each with an inconspicuous ultrasound finding. In addition, the average duration of the examination was determined.

RESULTS

The landmark structures could be demonstrated in all patients. Five planes were defined for each technique, and the course of the whole examination with 15 exact planes was described. The average duration of the examination was 4.5 minutes.

CONCLUSION

As of now, the digitally reconstructed anatomical illustrations have achieved the best image resolution and quality regardless of the position of the plane in the examination volume. The standardised course of the gynaecological ultrasound examination can serve as a basis for the improvement of training quality and the evaluation of a general gynaecological ultrasound screening.

Association between the mesenchymal compartment of uterovaginal organogenesis and local tumour spread in stage IB–IIB cervical carcinoma: a prospective study

BACKGROUND

Macroscopic, microscopic, and occult local tumour spread might be restricted to a permissive territory related to the morphogenesis of the tissue or organ from which the tumour originates. We aimed to define such a morphogenetic unit in Müllerian development, and to assess the role of total mesometrial resection in the treatment of patients with stage IB-IIB cervical carcinoma.

METHODS

We analysed uterovaginal development in serial sections of female human embryos and fetuses, and defined the distal Müllerian morphogenetic unit from the Müllerian mesenchyme. We assessed prospectively the histopathological and clinical findings from patients who underwent total mesometrial resection-modified surgery for stage IB-IIB cervical carcinoma that aims to remove the uterus, proximal vagina, and extracervical mesenchyme within the borders of the distal Müllerian morphogenetic unit.

FINDINGS

The spatial extension of the Müllerian mesenchyme, its vascularisation, and its innervation during early uterovaginal organogenesis determine a tissue territory that can be followed during fetal development and identified in women as a morphogenetic unit. 105 of 106 patients who had total mesometrial resection, 63 of whom were classed as high risk, had microscopically tumour-free resection margins (ie, R0). 48 (96%) of 50 patients had pelvic recurrence-free survival at 3 years (95% CI 92-100) without adjuvant radiotherapy.

INTERPRETATION

Radical en-bloc resection of a topographically defined anatomical territory derived from common precursor tissue leads to local tumour control, preservation of autonomic nerves, and a reduced need for adjuvant radiotherapy.

Three-dimensional reconstruction and quantification of cervical carcinoma invasion fronts from histological serial sections

The analysis of the three-dimensional (3-D) structure of tumoral invasion fronts of carcinoma of the uterine cervix is the prerequisite for understanding their architectural-functional relationship. The variation range of the invasion patterns known so far reaches from a smooth tumor-host boundary surface to more diffusely spreading patterns, which all are supposed to have a different prognostic relevance. As a very decisive limitation of previous studies, all morphological assessments just could be done verbally referring to single histological sections. Therefore, the intention of this paper is to get an objective quantification of tumor invasion based on 3-D reconstructed tumoral tissue data. The image processing chain introduced here is capable to reconstruct selected parts of tumor invasion fronts from histological serial sections of remarkable extent (90-500 slices). While potentially gaining good accuracy and reasonably high resolution, microtome cutting of large serial sections especially may induce severe artifacts like distortions, folds, fissures or gaps. Starting from stacks of digitized transmitted light color images, an overall of three registration steps are the main parts of the presented algorithm. By this, we achieved the most detailed 3-D reconstruction of the invasion of solid tumors so far. Once reconstructed, the invasion front of the segmented tumor is quantified using discrete compactness.

Expression of Apaf-1 in cervical cancer correlates with lymph node metastasis but not with intratumoral hypoxia

OBJECTIVES

The aim of this study was to investigate the expression of the proapoptotic protein Apaf-1 in cervical cancers. Moreover, we studied its correlation to intratumoral pO(2) and to clinico-pathological parameters.

METHODS

86 patients with cervical cancer were subjected to intratumoral pO(2) measurement with the Eppendorf electrode. From these patients, cervical cancer tissue was used for immunohistochemistry with an anti-Apaf-1 antibody.

RESULTS

Apaf-1 is expressed in cervical cancer. Cervical cancers with strong or moderate Apaf-1 expression had significantly less lymph node metastases at time of surgery than tumors with weak or negative Apaf-1 expression (P = 0.022). There was no significant correlation between Apaf-1 expression and intratumoral pO(2), pT stage, FIGO stage, lymphovascular space involvement, and grade.

CONCLUSIONS

Loss of Apaf-1 expression may represent a marker of aggressive tumor behavior since it correlates significantly with the occurrence of lymph node metastasis in cervical cancer.

Pathologisch-anatomische Aufarbeitung und Befundung von Lymphknoten bei gynäkologischen Malignomen

The nodal status is one of the strongest prognostic factors in gynecologic malignancies. Metastatic involvement of regional and distant lymph nodes represents the selection basis for adjuvant therapy in a large number of solid neoplasms. The number of resected lymph nodes is one of the most important parameters in the quality control of the surgical procedure, in particular with respect to radicality. The present paper provides recommendations for gross dissection, laboratory procedures and reporting for lymph node biopsies, lymph node dissections and sentinel lymph node biopsies (SLN) for cancers of the vulva, vagina, uterine cervix, endometrium, Fallopian tubes and the ovaries, submitted for the evaluation of metastatic disease. The pathologic oncology report should include information about the number and size of resected lymph nodes, the number of involved lymph nodes with the maximum size of metastases and the presence of paranodal infiltration. In addition, the detection of isolated tumor cells should be reported, particularly with respect to the detection method (immunostains or molecular methods). In cases of metastatic disease and carcinoma of unknown primary (CUP-syndrome), information should be given regarding the primary tumor.

Neue Konzepte für die operative Therapie des Zervixkarzinoms

Abdominal radical hysterectomy (Wertheim operation) is the current standard of surgical therapy of cervical carcinoma. It is based on historical concepts of female pelvic anatomy and locoregional tumor spread. This surgical therapy - depending on the individual radicality of the operation - leads to damage of essential structures not involved by the tumor, e.g. the autonomic pelvic nerves. Despite of its supposed radicality the Wertheim operation has to be combined with adjuvant radiotherapy in case of histopathological high risk factors to reach acceptable rates of tumor control. The total mesometrial resection (TMMR) uses new insights in pelvic anatomy and local tumor spread derived from developmental biology for a new concept of radicality achieving a high regional control rate with minimal treatment-related morbidity without adjuvant radiotherapy.

The hydra phenomenon of cancer: why tumors recur locally after microscopically complete resection

After surgical resection with microscopically clear margins, solid malignant tumors recur locally in up to 50%. Although the effect of a local tumor recurrence on the overall survival may be low in common cancers such as carcinoma of the breast or prostate, the affected patients suffer from exacerbated fear and the burden of the secondary treatment. With some tumor entities such as carcinoma of the uterine cervix or carcinoma of the head and neck, a local recurrence indicates incurability in the majority of cases. The pathomechanisms of local tumor spread and relapse formation are still unclear and comparatively little research has been devoted to their elucidation. Through the analysis of clinical and molecular data, we propose the concept of two pathogenetically and prognostically different local relapse types (i) in situ recurrences that arise in the residual organ/organ system not involved in the surgery for the primary tumor and (ii) scar recurrences that develop at the site of previous tumor resection. Whereas field cancerization, the monoclonal or multiclonal displacement of normal epithelium by a genetically altered but microscopically undistinguishable homologue, may explain the origin of in situ recurrences, most scar recurrences are regarded as the result of the interaction of minimal residual microscopically occult cancer with the surgical wound environment inside a developmentally defined tissue or organ compartment. The therapeutic implications derived from these concepts and areas of future research aimed to reduce local relapses are discussed in this perspective.

Microregional Expression of Glucose Transporter-1 and Oxygenation Status: Lack of Correlation in Locally Advanced Cervical Cancers

PURPOSE

Glucose transporter-1 (GLUT-1), a target gene of hypoxia-inducible factor-1, has been considered a candidate endogenous marker of tumor hypoxia. Expression of GLUT-1 may also serve as an indicator for the induction of the transcriptional response to hypoxia, which has been linked to enhanced proliferation, resistance to therapy, and metastatic propagation of cancer cells. Overexpression of GLUT-1 has been shown to correlate with poor prognosis in several tumor entities, among them cancers of the uterine cervix. The validity of these hypotheses is investigated.

EXPERIMENTAL DESIGN

The expression of GLUT-1 was assessed in 80 biopsies of Eppendorf oxygenation measurement tracks from locally advanced cervical cancers in 47 patients using immunohistochemistry.

RESULTS

No correlation was found between the expression of GLUT-1 and oxygenation variables (median pO2, HF 2.5 and HF 5). Expression of GLUT-1 was found greater in larger tumors (P = 0.0001) and to exhibit a linear increase with Federation Internationale de Gynecologie et d' Obstetrique stage (P = 0.002). Overall survival (P = 0.004) and recurrence-free survival (P = 0.007) were significantly shorter for patients with expression of GLUT-1. In the subgroup of patients treated with surgery, this effect on prognosis was not independent when pT stage or pN stage were included in a multivariate Cox proportional hazards model.

CONCLUSIONS

The suitability of GLUT-1 as an endogenous marker of tumor hypoxia seems questionable. The association with prognosis may partially depend on confounding factors.

A misdiagnosed case of caesarean scar pregnancy

CASE REPORT

We report a case of an ectopic pregnancy in a caesarean section scar, which was initially misdiagnosed despite using ultrasound. For the first time, a strongly vascularised pelvic tumour developed while the titre of serum human chorionic gonadotrophin decreased after a curettage abortion for an unwanted pregnancy.

OUTCOME

Due to uncontrollable haemorrhage, an emergency hysterectomy had to be performed 8 weeks later.