Changes in tumour morphology with alterations in oxygen availability: further evidence for oxygen as a limiting substrate.

The ability of cancer cells to survive at a distance from blood vessels should be dependent on the local supply of nutrients to each vessel. The corded growth of tumour cells around blood vessels within regions of necrosis in the RH carcinoma in the mouse allows the limit to which cells can be supported by individual vessels to be observed. The thickness of individual tumour cords was measured in conventionally stained tumour sections using a scanning technique to determine the distance between the blood vessel wall and the most distant viable cell adjacent to necrosis. Cord radius was found to vary with the oxygen supply conditions. Control animals had a mean radius of 105 +/- 2 microns while animals that had breathed 10% oxygen had significantly narrower cords (93 +/- 3 microns after 48 h) and animals breathing 100% oxygen had significantly wider cords (117 +/- 3 microns after 24 h). Mice made anaemic (mean hct. 28%) by phlebotomy and plasma transfusion had cord radii that were not significantly different from controls at any time up to 48 h. We conclude that this relatively slow growing mouse tumour is capable of rapid morphological adaptation (less than 3 h) to changes in nutrient availability and that oxygen is probably the limiting substrate.     

The Relationship Between Changes in Tumour Volume, Tumour Cell Density and Parenchymal Cord Radius in a Human Melanoma Xenograft Exposed to Single Dose Irradiation

A human melanoma xenograft, in which the viable tumour tissue formed cylindrical cuffs around blood vessels, was irradiated with single doses of 7.5 Gy and 15.0 Gy respectively. The nuclear density, the frequency of giant cells and the mean par-enchymal cord radius were measured and compared to the tumour growth response. After 7.5 Gy, the growth rate was only slightly reduced and there were no significant changes in the nuclear density or the mean parenchymal cord radius. After 15.0 Gy the mean parenchymal cord radius decreased the first week. This coincided with swelling of endothelial cell nuclei and reduced density of functional capillary-like vessels. Although the number of tumour cells declined, the tumour volume increased the first days after irradiation with 15.0 Gy since the cell density was reduced.     

Phenotype of tumor lymphatic vessels is a prognostic factor in human tongue squamous cell carcinoma

Tumor metastasis to lymph nodes occurs through the lymphatic vessels located in the tumor circumference. However, few studies have focused on the phenotypes of lymphatic vessels around these tumors. We investigated the characteristics of the lymph vessels of tongue squamous cell carcinoma (SCC) and compared them to clinicopathological characteristics. A total of 43 patients diagnosed as having tongue SCC consulted Hokkaido University Hospital were examined. The lymphatic vessels were identified by antibody D2-40 and the number and diameter of tumor lymphatic vessels were measured. The proliferative activity of lymphatic endothelial cells was also examined by immunostaining using antibody MIB-1. We then measured the DNA density of lymphatic endothelial cells in normal and tumor tissues. The number of tumor lymphatic vessels significantly increased in highly metastatic cases of tongue SCC, particularly in cases with a large number of micro lymphatic vessels. A significant correlation was found between the metastatic and proliferative activity of tumor lymphatic endothelial cells. Moreover, the DNA density of tumor lymphatic endothelial cells increased compared to normal tissues. These results suggest that the phenotypes of tumor lymphatic endothelial cells are an indicator of lymph node metastasis of tongue SCC.     

Vascular phenotype in angiogenic and non-angiogenic lung non-small cell carcinomas

We have previously described a group of non-small cell lung carcinomas without morphological evidence of neo-angiogenesis. In these tumours neoplastic cells fill up the alveoli and the only vessels present appear to belong to the trapped alveolar septa. In the present study we have characterised the phenotype of the vessels present in these non-angiogenic tumours, in normal lung and in angiogenic non-small cell lung carcinomas. The vessels, identified by the expression of CD31, were scored as mature when expressing the epitope LH39 in the basal membrane and as newly formed when expressing alphaVbeta3 on the endothelial cells and/or lacking LH39 expression. In the nine putative non-angiogenic cases examined, the vascular phenotype of all the vessels was the same as that of alveolar vessels in normal lung: LH39 positive and alphaVbeta3 variable or negative. Instead in 104 angiogenic tumours examined, only a minority of vessels (mean 13.1%; range 0--60%) expressed LH39, while alphaVbeta3 (in 45 cases) was strongly expressed on many vessels (mean 55.5%; range 5--90%). We conclude that in putative non-angiogenic tumours the vascular phenotype is that of normal vessels and there is no neo-angiogenesis. This type of cancer may be resistant to some anti-angiogenic therapy and different strategies need to be developed.     

Disparate responses of tumour vessels to angiotensin II: tumour volume-dependent effects on perfusion and oxygenation

Perfusion and oxygenation of experimental tumours were studied during angiotensin II (AT II) administration whereby the rate of the continuous AT II infusion was chosen to increase the mean arterial blood pressure (MABP) by 50-70 mmHg. In subcutaneous DS-sarcomas the red blood cell (RBC) flux was assessed using the laser Doppler technique and the mean tumour oxygen partial pressure (pO2) was measured polarographically using O2-sensitive catheter and needle electrodes. Changes in RBC flux with increasing MABP depended mainly on tumour size. In small tumours, RBC flux decreased with rising MABP whereas in larger tumours RBC flux increased parallel to the MABP. As a result of these volume-dependent effects on tumour blood flow, the impact of AT II on tumour pO2 was also mainly tumour volume-related. In small tumours oxygenation decreased with increasing MABP during AT II infusion, whereas in large tumours a positive relationship between blood pressure and O2 status was found. This disparate behaviour might be the result of the co-existence of two functionally distinct populations of tumour vessels. In small tumours, perfusion decreases presumably due to vasoconstriction of pre-existing host vessels feeding the tumour. In larger malignancies, newly formed tumour vessels predominate and seem not to have this vasoresponsive capability (lack of smooth muscle cells and/or AT receptors), resulting in an improvement of perfusion which is not tumour-related per se, but is due to the increased perfusion pressure.     

Comparison between the comet assay and the oxygen microelectrode for measurement of tumor hypoxia.

BACKGROUND AND PURPOSE: Hypoxic cells are present in some solid tumours and are known to limit radiocurability. To compare two measures of tumour hypoxia, 25 patients with locally advanced disease and accessible tumours or metastatic nodes were examined using an oxygen microelectrode and the alkaline comet assay. MEASUREMENTS AND METHODS: For the comet assay, fine needle aspirate biopsies were taken immediately following a dose of 5-10 Gy. Single cells were examined for radiation-induced DNA strand breaks, and the percentage of radio-resistant hypoxic cells within the population was calculated from DNA damage histograms. For oxygen tension (pO2) measurements, multiple tracks were made using an Eppendorf oxygen microelectrode. The possibility that application of the first method might influence hypoxic fraction measurement by the second method was examined in a more controlled system by creating four tracks in murine SCC-VII tumours using an oxygen electrode, and measuring hypoxic fraction at subsequent times. RESULTS: For 28 tumours from 25 patients, hypoxic fraction measured by comet assay correlated with the percentage of PO2 values < 5 mmHg (r2 = 0.46, P < 0.001). The mean comet hypoxic fraction was 0.36 for five tumours with a median PO2 < 10 mmHg. For the remaining 23 tumours with a median PO2 > 10 mmHg, the mean hypoxic fraction was 0.09. Advancement of an oxygen electrode through SCCVII tumours had no significant effect on hypoxic fraction measured 5 min to 24 h later using the alkaline comet assay. CONCLUSIONS: Tumours defined as hypoxic based on a median pO2 < 10 mmHg appear to contain more than 20% radio-biologically hypoxic cells as estimated by the comet assay. In an animal tumour model, puncture of the tumour with an oxygen electrode did not influence hypoxic fraction measured using the comet assay, in agreement with the clinical data that the order in which the two methods were performed was not important.     

Induction of vascular endothelial growth factor (VEGF) by hyperthermia and/or an angiogenesis inhibitor.

Intratumoral localization of vascular endothelial growth factor (VEGF) following administration of hyperthermia (HT) and/or anti-angiogenic drugs (TNP-470) was evaluated using SCC VII tumours in C3H/He mice. Hyperthermia at 44.0 degrees C for 30 min was given with a water bath on day 0. TNP-470 (100 mg/kg) was administered alone or after HT on day 0 and day 3. Histological changes on day 4 were evaluated by haematoxylin-eosin (HE) staining and immunohistochemical staining for VEGF. The percentage of the necrotic area relative to the entire tumour area (the % necrotic area) was measured on HE stains. The average % necrotic area of the untreated SCC VII tumours was 7%, while those of tumours treated with TNP-470 alone and HT alone were 27 or 65%, respectively. When HT and TNP-470 were combined, the % necrotic area was 82%, which was significantly higher than that caused by HT alone (p < 0.05). Immunohistochemical staining for VEGF in untreated SCC VII tumours was weak, although strong staining for VEGF was noted in untreated EMT-6 tumours of BALB/c mice, which have spontaneous central necrosis. After administration of HT and/or TNP-470, layer-shaped staining by VEGF was observed in the residual SCC VII tumour cells adjacent to the necrotic area. In conclusion, the expression of VEGF increased in response to administration of HT and/or TNP-470. Hypoxia caused by heat-induced vascular damage may be attributable to increased expression of VEGF in SCC VII tumours.     

DNA double-strand break rejoining rates, inherent radiation sensitivity and human tumour response to radiotherapy.

The relationship between DNA double-strand break rejoining rates, inherent radiation sensitivity and tumour response to radiation therapy was determined for a group of 25 squamous cell carcinoma (SCC) and eight sarcoma (SAR) tumours. DNA double-strand break frequencies were measured by neutral filter elution in first passage following explant tumour samples after in vitro exposure to 100 Gy of 60Co gamma-rays. There was no significant difference between SCC and SAR tumour cells in their sensitivity to break induction, but in a 1 h time period SAR tumour cells rejoined significantly fewer breaks than SCC tumour cells, consistent with the greater sensitivity of SAR and suggesting that differences in rates of break rejoining account for the different distributions of radiosensitivities seen when different tumour types are compared. The percentage of breaks rejoined in 1 h in these tumour samples correlated well with D(o) and with the beta component of the survival curve, measured in vitro by clonogenic assay in tumour cell lines established from the tumour samples, but not with SF2 or the alpha component of the survival curve. The rates of DNA double-strand break rejoining therefore appear to influence the exponential portion of survival curves and probably the interactions between breaks. The percentage of breaks rejoined in 1 h was higher in SCC tumours that subsequently failed radiotherapy and, although the differences were not significant, they suggest that rates of break rejoining are an important component of tumour response to radiation therapy.     

Tumor cord and growth in human brain tumors based on mathematical morphology

Summary The growth of human brain tumor was quantitatively investigated by using the anti-bromodeoxyuridine (BrdU) monoclonal antibody and the texture analyzing system (TAS). Tissues from thirty eight patients consisting of 22 gliomas, 8 brain metastases, 1 cerebellar hemangioblastoma and 7 normal white matters were applied in this study. Mean values of growth fractions (GFs) were 29.4% in group 1, 14.8% in group 2, and 6.5% in group 3. The higher value of GFs showed a significantly larger degree of perivascular aggregation of S-phase cells (DPAS). The mean number of cells in each tumor cord was approximately 20, which is not significantly larger than that of the normal group. But there was a significant difference between the non-selected area of the histologically malignant or benign gliomas and the proliferating area of the biologically malignant or benign brain tumors (t-value; p<0.001). A significant difference was also noticed in the mean area and diameter of tumor cords (t-value; p<0.001). From the point of view of biological behavior in human brain tumor, it is suggested that one tumor cord contains approximately 20 viable cells in the proliferating area in both benign and malignant brain tumors, and that if viable cells increase to more than 20 cells in one TC, necrotic cells and the diameter and area of the TC will increase, because the vessel-density is decreased by the occlusion of the vessels and the death of the endothels.     

Measurement of delivery and metabolism of tirapazamine to tumour tissue using the multilayered cell culture model

Purpose: Efficient extravascular penetration is essential for the optimal activity of most anticancer drugs and is particularly relevant to bioreductive cytotoxins which target hypoxic cells that can be located distal to functional blood vessels within tumours. Tirapazamine (3-amino-1,2,4-benzotriazine-1,4-di-N-oxide; Triazone; SR 259075; formerly SR 4233) is a lead bioreductive cytotoxin currently undergoing clinical evaluation. It exhibits preferential cytotoxicity towards cells at reduced oxygen tension, and could complement existing anticancer therapies where hypoxic cells are believed to constitute a refractory population. We assessed the ability of tirapazamine to penetrate tumour tissue using an in vitro multilayered cell culture (MCC) model. Methods: Diffusion of tirapazamine through oxic and hypoxic multilayered cell cultures composed of SiHa, human cervical carcinoma cells, was measured using a dual reservoir diffusion apparatus from which samples were quantified via HPLC. Drug concentration kinetics from both reservoirs were analysed using a mathematical model for diffusion and metabolism within the MCC. Results were then applied to a second mathematical model which described extravascular drug penetration within a tumour cord, the sheath of cells surrounding a blood vessel. Results: The diffusion coefficient of tirapazamine within SiHa MCCs was determined as 7.0±0.5×10⁻⁷ cm²/s and the maximal metabolic rate for hypoxic MCCs, V_max, as 1.5±0.4 M/s. The thickness of individual tissue cultures was determined by diffusion of tritiated water (HTO). A linear relationship was shown to exist between tissue thickness and the inverse of permeability to HTO. Experimental results were used to simulate drug distribution within a tumour cord. These simulations indicate that, when tirapazamine is administered via intravenous infusion, a stable tirapazamine distribution throughout the cord occurs within 15 min with cells most peripheral to the blood vessel exposed to only 10% of the blood drug concentration. Under these conditions, the simulations predict cell kill to be limited to the first 75 μm of tissue surrounding a blood vessel. Conclusions: This study indicates that extravascular penetration of tirapazamine to peripheral cells existing at low oxygen tension may be limited by the metabolism of tirapazamine by more proximal cells existing at moderate oxygen tension. Simulations found that tirapazamine reached only 10% of the blood concentration at cells most peripheral to blood vessels. These results indicate that tirapazamine would be significantly cytotoxic only to cells located within ∼75 m of blood vessels. Further MCC-based modelling of extravascular drug penetration would serve as a means of identifying new antitumour agents with location-specific activity. Received: 6 February 1998 / Accepted: 29 June 1998     

Detection of hypoxia by measurement of DNA damage in individual cells from spheroids and murine tumours exposed to bioreductive drugs. I. Tirapazamine.

The possibility of using tirapazamine (SR 4233) to identify hypoxic cells in multicell spheroids and murine tumours was examined by measuring tirapazamine-induced DNA damage to individual cells from multicell spheroids and SCCVII murine tumours. Fluorescence microscopy and image analysis were used to measure the extent of migration of DNA from individual cells embedded in agarose and exposed to an electric field. Using both the alkaline and neutral versions of the comet assay, at least 20 times more single-strand breaks were observed in cells from fully anoxic than fully oxic Chinese hamster V79 spheroids exposed to 30 microM tirapazamine, and about 10 times more single- than double-strand breaks were observed. Cells from spheroids containing about 50% radiobiologically hypoxic cells showed a pattern of tirapazamine breaks which translated to approximately 30% well-oxygenated in SCCVII tumors growing in C3H mice was also demonstrated. Cells close to tumour blood vessels showed less DNA damage by 20 mg kg-1 tirapazamine than cells distant from blood vessels. Rejoining of single-strand breaks was exponential, with a half-time of about 1 h under aerobic conditions, but rejoining half-time increased to 2 h for cells allowed to repair under anoxic conditions. While tirapazamine damage to DNA measured using the comet assay cannot provide a direct measure of hypoxic fraction, the degree of heterogeneity in DNA damage can be used to estimate the range and distribution of individual cell oxygen contents within spheroids and tumours.     

Association of vascular endothelial growth factor expression with intratumoral microvessel density and tumour cell proliferation in human epidermoid lung carcinoma.

Vascular endothelial growth factor (VEGF) expression, vascularisation and tumour cell proliferation were analysed in 91 human epidermoid lung carcinomas using immunohistochemistry. A polyclonal anti-VEGF antibody was used for VEGF expression, a polyclonal antibody directed against human von Willebrand factor (factor VIII) to identify blood vessels and the proliferating cell nuclear antigen (PCNA) as a marker for proliferating cells. Positive staining for VEGF was obtained in 54 out of 91 cases (59%), the number of blood vessels varied from zero to 64 counts (mean 9.4) and the proportion of PCNA-positive cells varied from 1.3% to 72.1% (mean 25.2%). The mean PCNA labelling index and mean microvessel count in VEGF-positive tumours were significantly higher than those in VEGF-negative tumours (Wilcoxon rank sum test, P<0.0001; p<0.05). In addition, PCNA labelling index significantly increased with increasing VEGF expression (Jonckheere test, P<0.0001). In contrast, no association was found between PCNA labelling index and tumour vascularity (r=0.07, P=0.48). The close correlation of VEGF expression with tumour cell proliferation and microvessel density suggests that VEGF acts both as an autocrine growth factor and as stimulator for angiogenesis. However, tumour cell proliferation and microvessel growth and/or density may be regulated by separate mechanisms.     

Frequencies of HER-2/neu expression and gene amplification in patients with oesophageal squamous cell carcinoma

The utilisation of antitumour T cells induced by cancer vaccination with HER-2 peptides or antibodies (Herceptin) against HER-2, as immunotherapy for oesophageal cancer, is a novel and attractive approach. It is important to clarify the frequencies of HER-2 expression and gene amplification in patients with oesophageal squamous cell carcinoma (SCC) and to evaluate the relationship between HER-2 status and HLA haplotype, since the candidates for HER-2 peptide-based vaccination are restricted to a certain HLA haplotype. We determined the frequency of HER-2 expression using the HercepTest for immunohistochemistry and HER-2 gene amplification by fluorescence in situ hybridisation (FISH) assay in oesophageal SCC (n=66). HER-2-positive tumours (1+/2+/3+) analysed by a HercepTest were observed in 30.3% of all the patients and HER-2 gene amplification evaluated by FISH was observed in 11.0% of all the patients, in which all HercepTest (3+) tumours were found to have gene amplification and three of six moderately positive (2+) tumours showed gene amplification. Furthermore, HER-2-positive cells were present more diffusely and were larger within each tumour in the patients who were HercepTest 3+ than those who were HercepTest 1+. Moreover, the survival rate in HER-2-positive group was significantly worse than that in HER-2-negative group. Also, the survival rate in the patients with HER-2 gene amplification was significantly worse than that without HER-2 gene amplification. In addition, oesophageal SCC patients with both HLA-A24-positive and HER-2-positive tumours (1+/2+/3+) accounted for 26% of these cases, and both HLA-A2- and HER-2-positive tumours accounted for 18% of them.     

Photofrin accumulation in malignant and host cell populations of various tumours.

Photofrin accumulation in malignant and host cell populations of various tumours was studied by flow cytometry analysis of cells dissociated from the tumour tissue. The transplantable mouse tumour models included in this analysis were sarcomas EMT6, RIF, KHT and FsaN, Lewis lung carcinoma, SCCVII squamous cell carcinoma (SCC) and slowly growing moderately differentiated AT17 SCC. An example of spontaneous mouse adenocarcinoma was also examined. Staining with specific monoclonal antibodies was used to identify the various cell populations present in these tumours. The main characteristic of Photofrin cellular accumulation was a very high photosensitiser content found exclusively in a subpopulation of tumour-associated macrophages (TAMs). Photosensitiser levels similar to or lower than in malignant cells were observed in the remaining TAMs and other tumour-infiltrating host cells. Photofrin accumulation in malignant cells was not equal in all tumour models, but may have been affected by tumour blood perfusion/vascularisation. Results consistent with the above findings were obtained with SCC of buccal mucosa induced by 9,10-dimethyl-1,2-benzanthracene in Syrian hamsters. The TAM subpopulation that accumulates by far the highest cellular Photofrin levels in tumours is suggested to be responsible for the tumour-localised photosensitiser fluorescence.     

Immunohistochemical distinction of high-grade mucoepidermoid carcinoma and epidermoid carcinoma of the parotid region

The correct diagnosis of high-grade mucoepidermoid (MEC), which is composed of solid islands of intermediate and squamous cells, may be challenging, due to its similarity to other tumours, mainly with squamous cell carcinoma (SCC). The present report employed immunohistochemical technique against different cytokeratins (CKs), in order to differentiate these two entities. : Six high-grade MEC and six SCC of the parotid region, retrieved from the files of both Oral Pathology Department of the School of Dentistry of University of S?o Paulo and Pathology Department of A.C. Camargo Hospital, were submitted immunohistochemical technique against Cks 7,8, 10, 13, 14 and 19. : High-grade MEC was positive for Cks 7, 8, 13, 14 and 19. The cases of SCC showed strong positivity for CK14, and CK10 was present only in focal areas. Our results highlight the use of CKs (especially CK14) to differentiate high-grade MEC and SCC.     

Les tumeurs rares de l’ovaire : stratégies thérapeutiques en 2010, Observatoire francophone des tumeurs rares de l’ovaire et émergence des centres de références

Majorities of the rare ovarian cancer were represented by Germ cell tumours and sex cords ovarian tumours with borderline tumours, clear cell carcinoma and mucinous carcinoma and are extremely rare malignant diseases of the ovaries. Tumors of the stromal (Leydig cells) and/or sex cords (Sertoli cells) represent approximately 7% of ovarian cancers and develop from the conjunctive tissue (respectively, interstitial and nurse cells) of the ovaries. All together, they represented less than 5% of the adult malignant and non malignant ovarian tumours. Treatment of rare ovarian tumors is currently as follows. Surgery is the same as that for ovarian adenocarcinoma, with one major difference: conservation of reproductive function in women of reproductive age is usual case for this type of tumor. Chemotherapy for germ cell and sex cords tumors, based on data reported in the literature is the same as that prescribed for testicular germ-cell tumors. For rare epithelial carcinoma, carboplatine plus paclitaxel remains the standard attitude with a well-known less efficiency than for other epithelial subtypes. Surgery, chemotherapy and possible surgical intervention for residual lesions are highly complex. Too rare to be included in randomized studies, treatment of these tumors has benefited from the therapeutic advancements made against testicular germ-cell tumors or with publications using retrospective data. Effectively, some prognostic factors such stage, histology, number of managed patients seems to be prognostic for survival. Because of the rarity of these tumours a specialized website (www.ovaire-rare.org) was developed in France in 2002. Objectives were: to delineate prognostic factors of these very rare diseases, to favour patient inclusion in a clinical trial available online, to provide access to online medical expert forum (disease-related) for complex cases, and finally to demonstrate the impact of these tools on improving medical practice. The website provides very interesting data for a better knowledge of these rare tumors and will possibly help improve medical practice. Since 2008, referent centers were delineated to promote optimal management of these tumors, organization of clinical and molecular research at a national or international level and to elaborate guidelines. The other new scientific data concern surgical procedures for sex cords tumors, evidence for presence of FOXL2 mutation in adult granulosa cell tumors, the use of paclitaxel plus carboplatine for sex cords tumors.     

Cell proliferation and vascularization in human breast carcinomas.

Cell proliferation and vascularization were studied in 10 human breast carcinomas by an immunoenzyme technique. The monoclonal antibody (MAb) Ki-67 was used as a marker for proliferating cells and a polyclonal antibody directed against human von-Willebrand factor to identify blood vessels. The proportion of Ki-67-labelled cells varied from 1% to 20%, the number of small blood vessels from 4.4/mm2 to 57.6/mm2. Within single histological sections of individual tumours the percentage of proliferating cells was not related to the number of small blood vessels. However, after evaluation of 5 sections of each tumour, the average values showed that tumours with a high grade of vascularization had a higher percentage of Ki-67-positive cells than poorly vascularized samples. The influence of vascular density on cell proliferation was investigated in a selected area of one of the tumours (in 2-dimensions) and with regard to the over- and underlying sections (in 3-dimensions). After 2-dimensional evaluation, distances from proliferating cells to the closest blood vessel between 10 and 390 microns were observed, and after 3-dimensional evaluation none of the proliferating cells measured was located more than 130 microns away from the closest vessel.     

The dynamics of tumor cords in an irradiated mouse mammary carcinoma with a large hypoxic cell component

The tumor cord model represents a histologically based framework for interpretation of radiobiological phenomena, particularly the resistance to radiation conferred by absence of oxygen. For the mammary carcinoma T50/80 grown in B6D2F1 male mice, average oxygenation was poor, based on tumor growth delay after irradiation. There was no improvement in radiobiological oxygenation for several days after a high dose of radiation. This was consistent with events in the cords of the tumor, where although up to 20% of all cells became pyknotic by 8 hr, the cords did not shrink for at least 2 days. The cellular kinetics of populations of intact and dead cells, adjacent to and remote from the capillaries of the cords, were examined for up to 60 hr after irradiation and it was found that: (i) before treatment, average LI (adjacent) was 13% and LI (remote) was 2%, (ii) after irradiation, cells expressed pyknosis after passing through the S phase of the cell cycle, so that (iii) at early intervals there was a larger proportional rise in pyknotic cells in the adjacent than the remote zone. However, (iv) at later intervals there was always a higher proportion of dead cells in the remote zone.     

The Dynamics of Tumor Cords in an Irradiated Mouse Mammary Carcinoma with a Large Hypoxic Cell Component

The tumor cord model represents a histologically based framework for interpretation of radiobiological phenomena, particularly the resistance to radiation conferred by absence of oxygen. For the mammary carcinoma T50/80 grown in B6D2F1 male mice, average oxygenation was poor, based on tumor growth delay after irradiation. There was no improvement in radiobiological oxygenation for several days after a high dose of radiation. This was consistent with events in the cords of the tumor, where although up to 20% of all cells became pyknotic by 8 hr, the cords did not shrink for at least 2 days. The cellular kinetics of populations of intact and dead cells, adjacent to and remote from the capillaries of the cords, were examined for up to 60 hr after irradiation and it was found that: (i) before treatment, average LI (adjacent) was 13% and LI (remote) was 2%, (ii) after irradiation, cells expressed pyknosis after passing through the S phase of the cell cycle, so that (iii) at early intervals there was a larger proportional rise in pyknotic cells in the adjacent than the remote zone. However, (iv) at later intervals there was always a higher proportion of dead cells in the remote zone.     

Cytokeratin fragment 19 and squamous cell carcinoma antigen for early prediction of recurrence of squamous cell lung carcinoma

Sixty patients with squamous cell carcinoma (SCC) of the lung, including 25 cases with recurrence and 35 cases without recurrence 1 year after operation, were enrolled in this study. The serial serum levels of cytokeratin fragment 19 (CYFRA 21-1) and SCC antigen were measured before operation and 1 week, 1 month, 3 months, 6 months, 9 months, and 12 months after operation for early detection of recurrence. The results revealed that 1) mean serum values of CYFRA 21-1 were significantly higher at early and any times after operation in 25 patients with recurrent SCC when compared with 35 patients without recurrent SCC; and 2) mean serum values of SCC antigen were significantly higher until 9 and 12 months after operation, in 25 patients with recurrent SCC when compared with 35 patients without recurrent SCC. We conclude that CYFRA 21-1 is a better marker than SCC antigen for early prediction of SCC recurrence in the lung.