Inhibition of tumor-cell attachment to extracellular matrix as a method for preventing tumor recurrence in a surgical wound

Prognostic Value of Intratumoral Collagen Quantification in Canine Oral Melanomas

The majority of the melanocytic neoplasms are considered malignant and highly metastatic. However, a subset of the melanocytic tumors has a more favorable prognosis and the identification of precise prognostic markers for this neoplasm may be useful to guide treatment. The collagen architecture and density have been shown to correlate with tumor progression in human breast cancer and canine mast cell tumors. The purpose of the present study was to investigate the prognostic value of the intratumoral collagen index (ICI) as an indicator of postsurgical survival and its relation with other prognostic markers for canine oral melanomas (OMs). Twenty-two cases were tested for intratumoral collagen density using Masson's trichrome stain and morphometry. No differences were found between dogs regarding survival. The ICI was not correlated with proliferative activity or nuclear atypia. The results presented herein indicate that the quantity of intratumoral collagen in canine OMs is not an efficient indicator of postsurgical survival. Complementary studies about the expression and activity of enzymes that are capable of degrading extracellular matrix (ECM) components are necessary.

VEGF Expression, Cellular Infiltration, and Intratumoral Collagen Levels after Electroporation-Based Treatment of Dogs with Cutaneous Squamous Cell Carcinoma

Canine cutaneous squamous cell carcinoma (SCC) is the most common type of skin cancer in tropical countries and is generally associated with exposure to solar ultraviolet light. It has a low metastatic rate, and local treatments, such as electrochemotherapy (ECT), promote long-term control or even complete remission. This study aimed to evaluate pre- and post-ECT treatment expression levels of vascular endothelial growth factor (VEGF) and CD31, cellular infiltration, and intratumoral collagen levels in dogs with cutaneous SCC. A prospective nonrandomized clinical study was performed using dogs with spontaneous SCC treated with ECT. Eighteen lesions from 11 dogs were included in the study. The expression levels of VEGF and CD31; cellular infiltration; and intratumoral collagen levels, as determined by Masson’s trichrome staining, were not significantly different from pre-treatment measurements on day 21 (p > 0.05). However, among cellular infiltration, the mixed subtype was correlated with better overall survival time when compared to lymphoplasmacytic and neutrophilic infiltration (p < 0.05). In conclusion, ECT had no effect on VEGF expression, cellular infiltration, or intratumoral collagen levels in dogs with cutaneous SCC at the time of evaluation, suggesting that early and late post-ECT-treatment phases should be considered.

Intratumoral collagen index predicts mortality and survival in canine cutaneous mast cell tumours

BACKGROUND

Mast cell tumours (MCTs) constitute almost 25% of cutaneous neoplasms in dogs. Their biological behaviour is predicted using histopathological grading which is based on several subjective criteria that are vulnerable to intra- and interobserver variability. To improve the prediction of the biological behaviour, several complementary markers have been studied. The integrity of the extracellular matrix (ECM) may play a protective role against tumoral progression, and favour cellular proliferation, angiogenesis, invasion and metastases when altered.

HYPOTHESIS/OBJECTIVES

To evaluate the quantification of collagen and elastic fibres as prognostic markers for MCTs.

ANIMALS

Thirty-eight random cases of canine cutaneous MCT surgically treated with wide margins were included.

METHODS AND MATERIALS

Intratumoral collagen and elastic fibres were identified and quantified on histological sections stained with Masson's trichrome, Picrosirius red and Verhoeff; the results were compared with histopathological grades, mortality due to the disease and postsurgical survival.

RESULTS

Morphometric analysis revealed a significant relationship between histopathological grade and intratumoral collagen index (CoI). In addition, the CoI was considered an independent indicator for mortality and postsurgical survival.

CONCLUSIONS AND CLINICAL IMPORTANCE

These results support the importance of the CoI in the grading and prognosis of MCTs, suggesting that preservation and/or synthesis of collagen have the potential to become targets for MCT therapeutics.

Percutaneous endoscopic gastrostomy site metastasis from head and neck squamous cell carcinoma: case series and literature review

Objectives

To present our experience with head and neck squamous cell carcinoma (HNSCC) seeding of percutaneous endoscopic gastrostomy (PEG) sites and to review all reported cases to identify risk factors and develop strategies for complication avoidance.

Materials and methods

The records of 4 patients with PEG site metastasis from HNSCC were identified from the authors’ institution. Thirty-eight further cases were reviewed following a PubMed search and evaluation of references in pertinent articles.

Results

Review of 42 cases revealed the average time from PEG to diagnosis of metastatic disease to be 8 months. Average time to death from detection of PEG disease was 5.9 months. One-year survival following PEG metastasis was 35.5% with an overall mortality of 87.1%.

Conclusion

PEG site metastatic disease portends a poor prognosis. Early detection and aggressive therapy may provide a chance of cure. Changes in PEG technique or in timing of adjunctive therapies are possible avenues in further research to prevent this complication.

EFFICACY OF CYTOTOXIC AGENTS FOR PREVENTION OF TUMOR GROWTH AFTER TUMOR CONTAMINATION AND BLOCKS INOCULATION: AN IN VIVO COMPARATIVE STUDY OF CISPLATIN AND DISTILLED WATER, POVIDONE IODINE, HYDROGEN PEROXIDE AND SALINE IN ATHYMIC MICE

We tested the efficacy of 4 local agents for protection against tumor growth after tumor contamination and tumor bloc inoculation. Tumors were prepared by injecting human HT-1080 fibrosarcoma cells into the subcutaneous tissue of 6–9 week old male athymic nude mice (BALB/c nu/nu). When the tumors reached the desired size, the nude mice were sacrificed, and the tumors were harvested en bloc. Then the tumors were used in either contamination group or tumor inoculation group. In the contamination group, 34 tumors were cut by Gigli saw (Group G) and 35 tumors were cut by No. 11 scalpel (Group S). The cut surface of the tumor was rubbed into the subcutaneous tissues of non-tumor bearing nude mice for 10 seconds. Then, the nude mice from the S and G groups were randomized into either one of five subgroups: groups S–N and G–N: no local agent was used, groups S–S and G–S: lavage by saline, groups S–P and G–P: lavage by povidone iodine 10%, groups S–H and G–H: lavage by hydrogen peroxide 3%, groups S–C and G–C: lavage by cisplatin and distilled water. In the tumor inoculation group, a tumor weight of 100 mg was inoculated into 32 non-tumor bearing nude mice. Then, the nude mice were randomized into either of 5 subgroups: group B–N: no local agent was used, group B–S: lavage by saline, group B–P: lavage by povidone iodine 10%, group B–H: lavage by hydrogen peroxide, group B–C: lavage by cisplatin and distilled water. For lavage, the fluid was kept in the wound for 5 minutes apart from the cisplatin which was kept in the wound for 2.5 minutes and then the wound was filled with distilled water for the next 2.5 minutes. Tumor growth occurred in S–N, S–S, S–H, S–P and S–C groups in 33.3%, 67.7%, 16.7%, 16.7%, and 0% respectively. Tumor growth occurred in G–N, G–S, G–H, G–P, and G–C groups in 50%, 67.7%, 33.3%, 33.3%, and 0%, respectively. The total growth incidence after tumor contamination in the no-agent, saline, hydrogen peroxide, povidone iodine and cisplatin groups were 41.7%, 58.3%, 25%, 25% and 0%, respectively. Growth occurred in 100% of B–N and B–S groups, 83% of B–H and B–P groups and 33.3% of the B–C group. Cisplatin used for 2.5 minutes followed by distilled water for 2.5 minutes is effective for protection against local tumor recurrence due to tumor contamination. It also has a reasonable effect against tumor blocks.

GROWTH AFTER RUBBING BY TUMOR CUT SURFACE: COMPARATIVE STUDY BETWEEN THREADWIRE SAW-CUT AND BLUNTLY-CUT TUMORS

Spondylectomy for extripation of spinal tumors would be performed through piecemeal excision or by total en bloc spondylectomy with cutting at the neural arch by the threadwire saw (T-saw) that is sometimes inevitably intralesional. The purpose of this study was to compare the potential for tumor growth after rubbing of the cut surface of tumors cut by either T-saw or blunt instrument against the subcutaneous tissues of nude mice. Tumors were prepared by subcutaneous injection of human HT 1080 fibrosarcoma cells in nude mice. The animals were sacrificed, and tumors were harvested en bloc and cut with either a T-saw or artery forceps. A 3-cm wound was created on the backs of other (plain) nude mice. The tumor's cut surface was rubbed for 10 seconds against the subcutaneous tissue of one of these nude mice. The wounds were then sutured. Tumor blocks were inoculated into other nude mice. Nude mice were followed for occurrence of tumor growth. Tumor growth occurred in all nude mice after block inoculation. The incidence of tumor growth after rubbing with the tumor surfaces cut with T-saw and artery forceps were 16.7% and 58.3% respectively (P = 0.035). Onset of tumor growth after tumor rubbing and inoculation of tumor blocks were 30.1 ± 25 and 12.2 ± 5 days respectively (P = 0.015). Rubbing of T-saw-cut tumor surface has less possibility of causing tumor growth than rubbing of surface of bluntly-cut tumors.

[Functional arginine-containing amino acid sequences in peptides and proteins]

L-arginine is a source of nitrogen oxide and plays a great role in a number of other biochemical processes. Functions and prospects for practical application of five groups of arginine-containing amino acid sequences and synthetic polyarginine sequences are considered. The physiological characteristics of well-known arginine-containing peptides, such as RGD peptides, kyotorphin, and tuftsin, are described in detail. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2008, vol. 34, no. 2; see also http://www.maik.ru

Systemic effects of surgery: quantitative analysis of circulating basic fibroblast growth factor (bFGF), Vascular endothelial growth factor (VEGF) and transforming growth factor beta (TGF-beta) in patients with breast cancer who underwent limited or extended surgery

BACKGROUND

To assess if feature, extent and duration of surgery could influence levels of systemic proangiogenic cytokines vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and transforming growth factor beta (TGF-beta).

PATIENTS AND METHODS

We collected blood samples from 82 consecutive breast cancer patients who underwent various types of surgery, classified according to the magnitude of tissue injury in: minimal (quadrantectomy), moderate (mastectomy without reconstruction), and heavy [mastectomy followed by reconstruction with transversus recto-abdominal muscle cutaneous flap (TRAM)]. Samples were collected one day before surgery (D(-1)), at the end of surgical tumor removal (D0), and on 1st (D(+1)), 2nd (D(+2)) and 5th (D(+5)) day after surgery. Serum VEGF, bFGF and TGF-beta levels were measured by the enzyme immunoassay method.

RESULTS

On average a continuous decrease was observed for all growth factors from the day before operation to the 5th day after operation. On day (D(+5)) an increase was observed for patients who underwent extended respect to moderate surgery. These differences were found statistically significant for bFGF and VEGF (p = 0.05 and p = 0.025 respectively). A statistically different trend for type of operation was observed also for TGF-beta at 24-48 h: a minor reduction, compared to time of operation, was observed for minimal surgery, an intermediate reduction for moderate surgery and a higher decrease for extended surgery.

CONCLUSIONS

Angiogenic cytokines perioperative levels could be increased on 5th day (D(+5)) by extent of surgery and should induce perioperative stimulation of residual cancer cells. A better understanding of the time interval during which the sequelae of events in wound healing occur may be the basis for defining new therapeutic strategies that can interfere with tumor outgrowth sparing wound healing processes.

Irrigation of port sites: prevention of port site metastases?

INTRODUCTION

Port site metastases can occur when free viable tumor cells implant at trocar wounds. Irrigation of port sites with cytotoxic agents has been suggested to prevent port site metastases. The objective of this study is to assess whether tumor growth at port sites can be reduced by irrigation of these port sites.

METHODS

WAG rats were insufflated with CO(2) for 20 minutes and 5 x 10(5) CC531 tumor cells were injected intraperitoneally. Port sites were irrigated after completion of the pneumoperitoneum with povidone-iodine, a mixture of taurolidine and heparin, or sodium chloride. Controls did not undergo any irrigation of port sites. In experiment 1, all 16 rats had all 4 irrigation modalities. In experiment 2, four groups of 20 rats had one type of irrigation on two trocar wounds. Tumor growth was evaluated 4 weeks after the procedure.

RESULTS

No difference in tumor growth at trocar wounds was found between any type of irrigation and controls in both experiments.

CONCLUSION

In this experimental model, no beneficial or adverse effects of irrigation of port sites could be shown.

Tumor growth potential after tumoral and instrumental contamination: an in-vivo comparative study of T-saw, Gigli saw, and scalpel

In the field of spinal tumors, intralesional tumor cutting is sometimes inevitable. The purpose of this study was to compare the potential for tumor growth after intralesional cutting by T-saw, Gigli saw, and scalpel. Tumors, prepared by the subcutaneous injection of human HT 1080 fibrosarcoma cells in nude mice, were harvested and cut with a T-saw, Gigli saw, or scalpel. A 3-cm wound was created in the skin on the back in another group of nude mice. The cut surface of the tumor was rubbed for 10 s against the subcutaneous tissue in this second group of nude mice. In the same manner, the instrument used for tumor cutting was rubbed against the subcutaneous tissue in the 3-cm wound in the back of a third group of nude mice for 10 s. Other instruments used for tumor cutting were immediately washed in culture medium, and the total number of tumor cells was counted. Tumor blocks and single-cell suspensions prepared from tumor tissues of the same weight were inoculated and injected into a fourth group of nude mice. The incidence of tumor growth after the rubbing of the subcutaneous tissue with the tumor surface cut with a T-saw, Gigli saw, and scalpel was 16.7%, 50.0%, and 33.3%, respectively. The corresponding figures after the rubbing of the subcutaneous tissue with a T-saw, Gigli saw, and scalpel was 16.7%, 33.3%, and 33.3%, respectively. The mean numbers of tumor cells attached to the T-saw, Gigli saw, and scalpel were 1.88 x 105, 5.02 x 105, and 4.92 x 105, respectively. Finally, the incidence of tumor growth after the inoculation of tumor blocks and single-cell suspensions was 100% and 77.8%, respectively. These findings show that tumor recurrence is less likely after intralesional tumor cutting with a T-saw than after such cutting with a Gigli saw or scalpel.

Metastasis of head and neck carcinoma to the site of percutaneous endoscopic gastrostomy: case report and literature review

BACKGROUND

Patients with head and neck cancer often need a percutaneous endoscopic gastrostomy to provide adequate nutrition because of inability to swallow after tumor radiation therapy. However, metastasis of the original tumor to the gastrostomy exit site may occur.

METHODS

We describe the case of a 61-year-old man with stage III (T2 N1) squamous cell carcinoma of the tongue in whom a PEG tube was placed to circumvent anticipated difficulties in swallowing after radiation therapy. We also compare this case with similar cases in the literature.

RESULTS

Soreness and erythema near the gastrostomy site reported by the patient were diagnosed as cellulitis, and two courses of antibiotic treatment were prescribed. However, a biopsy showed that the original squamous cell carcinoma had metastasized to the gastrostomy exit site. The "pull" method of tube placement had been used in this patient and in all 19 cases of metastasis reported in the literature.

CONCLUSIONS

Metastatic cancer should be considered in patients with head and neck cancer who have unexplained skin changes at the gastrostomy site. Our experience with this case and review of the literature indicate that, in patients with head and neck cancer, "pull" procedures for placement of gastrostomy tubes may induce metastasis by direct implantation of tumor cells because of contact between the gastrostomy tube and tumor cells. Methods of tube insertion that avoid such contact are preferred.

Cancer and laparoscopy, experimental studies: a review

OBJECTIVE

To review the experimental studies on laparoscopy and cancer and to propose guidelines for the clinical management of gynecologic cancer.

METHODS

The literature in MEDLINE was searched from January 1992 to December 1998 using the terms 'cancer', 'laparoscopy' and 'experimental or animal study'. Cross-referencing identified additional publications. Abstracts and letters to the editor were excluded. All the relevant papers were reviewed.

RESULTS

Depending on the model used, controversial results have been reported on the incidence of trocar site metastasis when comparing CO(2) laparoscopy and laparotomy. In contrast, the following conclusions can be proposed: (i) tumour growth after laparotomy is greater than after endoscopy; (ii) tumour dissemination is worse after CO(2) laparoscopy than after laparotomy; (iii) some of the disadvantages of CO(2) laparoscopy may be treated using local or intravenous treatments or avoided using other endoscopic exposure methods, such as gasless laparoscopy.

CONCLUSIONS

The laparoscopic treatment of gynecologic cancer has potential advantages and disadvantages, and may only be performed in prospective clinical trials. The risk of dissemination appears high when a large number of malignant cells are present. Adnexal tumours with external vegetations, and bulky lymph nodes should be considered as contra-indications to CO(2) laparoscopy.

Inhibition of peritoneal tumor cell growth and implantation in laparoscopic surgery in a rat model

BACKGROUND

The pathogenesis of portsite recurrences after laparoscopic surgery is still unknown, and a generally accepted approach to prevent tumor implantation does not exist.

METHODS

The effect of taurolidine and heparin on growth of colon adenocarcinoma DHD/K12/TRb was measured in vitro and in vivo. After incubation of the cells with heparin or taurolidine or both substances, cell kinetics were determined. In a rat model (n = 60), tumor cells were administered intraperitoneally, and pneumoperitoneum was established over 30 minutes. Rats received tumor cells, tumor cells + heparin, tumor cells + taurolidine, or tumor cells + taurolidine + heparin.

RESULTS

In vitro, tumor cell growth decreased after incubation with taurolidine and taurolidine/heparin. In vivo, intraperitoneal tumor weight was lower in rats receiving heparin (298 +/- 155 mg) and taurolidine (149 +/- 247 mg) compared with the control group (596 +/- 278 mg) but even less when both substances were combined (21.5 +/- 36 mg).

CONCLUSION

Heparin inhibits intraperitoneal tumor growth in vivo slightly, while taurolidine causes significant decrease of tumor cell growth in vitro as well as tumor take and intraperitoneal tumor growth in vivo.

The potential role of integrin receptor subunits in the formation of local recurrence and distant metastasis by mouse breast cancer cells

BACKGROUND

The mechanisms by which surgical injury fosters tumor growth are examined.

METHODS

TA3Ha mouse breast tumor line and its subline (TA3AD) differing in their metastatic abilities as tested by two models were used. In model a, TA3Ha/TA3AD tumors were grown in the mammary fat pads of mice and then surgically removed with a curative intent. In model b, TA3Ha/TA3AD cells were injected intravenously into mice subjected to liver or spleen wedge resection. Frequency of tumor formation at various sites was assessed. Expression of integrin, immunoglobulin, and proteoglycan cell adhesion receptors on TA3Ha and TA3AD cells was examined by flow cytometry. The roles of these receptors in metastasis were examined by blocking them by selected ligands and/or antibodies.

RESULTS

Frequencies of local recurrence and axillary metastasis after surgical resection, were 43% (32/74), and 37% (27/74) with TA3Ha tumors and 4% (1/29) at both sites with TA3AD tumors. Tumors at surgically injured spleen and the liver were seen in 75% (141/189) and 45% (107/240) of the mice with TA3Ha cells and in 8% (3/38) and 10% (4/42) of the mice with TA3AD cells. alpha 5 and CD44 receptors were expressed by TA3Ha cells but not by TA3AD cells. Other receptors examined were similarly expressed by both cell lines. Blocking of alpha 5 receptor by fibronectin reduced tumor implantation in a dose-dependent manner.

CONCLUSIONS

The data suggest a correlation among the ability to implant at surgically injured sites, to form local recurrence, and to express the fibronectin receptor subunit.

Adhesion receptors in malignant transformation and dissemination of gastrointestinal tumors

Changes in the expression and function of adhesion molecules on the surface of cancer cells are important characteristics in the development of gastrointestinal malignancies and might be used in the future as prognostic factors or as new targets for diagnostic and therapeutic approaches. In esophageal cancer a down-regulation of the E-cadherin receptor and the cytoplasmic protein alpha-catenin is associated with tumor dedifferentiation, infiltrative growth and lymph-node metastasis. In gastric cancer a reduction of E-cadherin expression due to gene mutations is restricted to diffuse-type tumors while the occurrence of the CD44-standard and the CD44-9v isoform is significantly related to a higher tumor-induced mortality and a shorter survival time. The CD44-6v isoform is predominantly expressed by intestinal-type gastric carcinomas, giving these tumor cells the ability to perform lymph-node metastasis. In pancreatic cancer the expression of integrin adhesion receptors is significantly altered during the malignant transformation while a loss of the E-cadherin receptor can generate dedifferentiation and invasiveness of pancreas carcinoma cells. There is increasing evidence that integrin receptors as well as different isoforms of the CD44 receptor are altered following the malignant transformation of colonic mucosa into adenomas and invasive carcinomas. The expression of the CD44-6v isoform seems to be associated with an adverse prognosis in colorectal cancer due to the development of tumor metastases. A strong correlation has been observed between the expression of the 67-kDa laminin receptor and the degree of differentiation, the invasive phenotype and the metastatic abilities af colorectal cancer cells. Analyzing the expression of the E-cadherin receptor showed that this receptor may serve as an independent prognostic marker in Dukes' stage B colorectal cancer to identify patients with poor prognosis and designate them for intensive adjuvant therapy and clinical observation after curative surgical tumor treatment.

Role of cytokines and growth factors in promoting the local recurrence of breast cancer

The pathogenesis of local recurrence in breast cancer is not well understood. Breast-conserving surgery is particularly prone to local recurrence as it leaves behind breast tissue that may harbour occult cancer, and lends itself to enhanced intraoperative shedding of cancer cells due to narrower resection margins and transection of lymphatic channels. A review of clinical breast cancer studies as well as experimental research strongly suggests that these persisting cancerous cells are unlikely to develop into clinically evident disease if their environment remains unstimulated. However, an inordinately high local recurrence rate occurs at the surgical scar, and such recurrence must be triggered by the release of growth factors and cytokines into the healing wound. These factors can stimulate any available cancer cells which express the proper growth factor receptors. Perioperative strategies to neutralize this tumour cell-growth factor interaction should maximize local control.

Inhibition of bladder tumor cell implantation in cauterized urothelium, without inhibition of healing, by a fibronectin-related peptide (GRGDS)

BACKGROUND

Local recurrence after transurethral resection of bladder tumors (TURB) is common and might be diminished if free tumor cells within the bladder are prevented from reattaching.

METHODS

In vitro inhibition of murine bladder tumor cells to an approximation of urothelial matrix with agents that might block attachment to components of the extracellular matrix, and in vivo inhibition of attachment in cautery-injured murine bladder.

RESULTS

GRGDS, (0.1-2.5 mg/ml), a fibronectin-related peptide, mannose-6-phosphate, (0.1-20 mg/ml), a carbohydrate, and heparin (1-625 units/ml) all inhibited attachment in vitro in a dose-dependent fashion. YIGSR (0.1-2 mg/ml), a laminin-related peptide, did not. Mannose (10 mg/ml) did not significantly inhibit attachment of tumor cells to cauterized urothelium in vivo, whereas there was a 77% reduction of attachment in bladders irrigated with GRGDS (6.25 mg/ml) (p < 0.05), and the appearance of subsequent tumors in the bladder was inhibited. Finally, GRGDS (6.25 mg/ml) did not inhibit healing of the cautery ulcer.

CONCLUSIONS

RGD-containing peptides may be useful as adjuvant therapy to decrease local recurrence after TURB and perhaps in other circumstances in which tumor cells spilled into a wound or body cavity threaten surgical success.

Quantitative comparison of xenotransplantation of a human soft tissue sarcoma into the subcutaneous tissue of normal, postincision, and postincision plus indomethacin-treated nude mice

The purpose of this study was to test the hypotheses that (1) surgical wounding can enhance the xenotransplantability of a human soft tissue sarcoma (HSTS26T) into subcutaneous (s.c.) tissue of nude mice, and (2) Indomethacin may reduce the xenotransplantability of this human tumor in the surgical wounding animal model by suppressing angiogenesis. The experimental method was to employ the quantitative transplantation assays (TD50, the number of tumor cells that, on average, would be expected to induce a tumor in 50% of the recipients). After an incisional wound (1.0-1.2 cm long) was made on the right leg of each experimental mouse, tumor cells were inoculated into the surgical wound, or into the contralateral leg at 24 and 72 hr postincision, and in another group tumor cells were inoculated into the wound at 72 hr postincision, plus daily s.c. injection of indomethacin, 2 mg/kg body weight for 8 consecutive days in a separate experiment. Nonincisional mice received the same inoculation as the control groups. The TD50s of surgically wounded groups were 3.5-10.7 times lower than that of the control groups. Significantly lower TD50 values were found in groups of cells inoculated into the surgical wound at 72 hr postincision (P < 0.05 or P < 0.01) and into the contralateral leg at 24 hr postincision (P = 0.05). No significant difference was found between the TD50 values in mice that received cells inoculated at 72 hr postincision plus indomethacin treatment, and those with no wound controls. Our conclusion is that the surgical wound can enhance the xenotransplantability of HSTS26T in nude mice. Indomethacin can decrease this enhancing effect level similar to that in no-wound controls and may prevent tumor recurrence in a surgical wound.

Growth and metastasis of human breast cancers in athymic nude mice

To evaluate critically the merit of utilizing a wound model for growing human tumors, a series of increasingly difficult human tumor types were tested for growth at sites of trauma in athymic nude mice. In vitro tumor lines as well as fresh tumors from the breast, colon, rectum, lung, and a metastasis from an unknown primary were intraperitoneally injected into mice subjected to intra-abdominal organ injury. Successful xenografts were obtained from nine of 10 cell lines and 14 of 24 fresh tumors. The latter included five of six (83%) colon cancers, one lung tumor, metastatic tumor of unknown primary, three of four (75%) metastatic breast cancers and four of six (67%) estrogen receptor (ER)-negative breast primary tumors. Six ER-positive breast tumors tested failed to grow in mice without estrogen supplementation. Xenografts from two breast, two colon and the lung cancers formed spontaneous metastases and all xenografts tested were able to yield serial transplants in the surgical wound model. Histologically, all xenografts and their metastases were identical to their respective donor tumors. Transplantability in mice without exogenous estrogen supplementation was linked to the absence of estrogen and progesterone receptors in breast tumors. Transplantability of the cell lines was associated with the expression of cell surface receptors for fibronectin and hyaluronic acid. Receptors for other extracellular matrix components, namely, laminin, vitronectin, collagen, fibrinogen or von Willebrand factor were not associated with transplantability. These results demonstrate that a large proportion of human tumors, including the breast tumors, can be successfully xenografted into athymic mice by providing them with a healing wound environment, and that such xenografts grown at ectopic sites exhibit metastatic ability.

Effect of trauma on implantation of metastatic tumor in bone in mice

We studied the influence of surgical trauma to the iliac bone on the implantation of I.V. injected tumor cells, which formed tumor in the surgical wounds of 27/84 mice (32%). None of these mice or nonsurgical mice developed tumor in the opposite or uninjured pelvic bone (P < 0.0001). When different numbers (10(5), 5 x 10(5), and 10 x 10(5)) of TA3Ha cells were injected I.V. immediately after surgery, the frequency of tumor formation showed an increase (respectively, 32%, 63%, 71%). As the interval between induction of trauma and tumor cell injection was increased from 0 to 15 days, the frequency of tumor formation declined from 32% to 0%. These results suggest that the healing wound is a privileged site for experimental metastasis, particularly in the early stages. It is likely that the proteins in the blood clotting cascade are involved in local tumor implantation.

Irrigation does not dislodge or destroy tumor cells adherent to the tumor bed

Local recurrences in the surgical bed after tumor resection may be due to residual tumor cells "dropping" into the wound. Irrigation with water is often used to remove these cells. We designed experiments to determine whether irrigation would prevent tumor recurrence. Surgical wounds of uniform size in C57BL/6 mice were seeded with 5 x 10(2), 5 x 10(3), 5 x 10(4), 5 x 10(5), or 5 x 10(6) viable syngeneic B16-F10 melanoma cells to test the hypothesis that irrigation with water would decrease local tumor recurrence. The tumor-contaminated wounds were irrigated with distilled water or with saline (0.9% NaCl) immediately or 5, 30, 60, 120, or 240 min after seeding. Control wounds were seeded but not irrigated. The technique of irrigation was altered in a second group of experiments such that the amount of time the tumor cells were exposed to the water or saline was 5, 10, or 15 min. To determine the rapidity and durability of tumor cell attachment to host tissue, 1 x 10(4) viable B16-F10 tumor cells were seeded in vitro onto freshly cut disks of syngeneic mouse dermis. The tissue was irrigated with saline or distilled water 0, 2, 5, 10, 15, 30, 60, 120, or 240 min later. Tumor growth was observed in all the mice and neither the mechanical action of irrigation nor the hypotonic effect of distilled water changed the rate of growth. Scanning electron microscopy (SEM) demonstrated stable and firm attachment to mouse tissue within seconds of seeding with no noticeable dislodgement or cytotoxicity by either saline or water irrigation. The data suggest that the commonly used technique of irrigating the bed of the resected tumor may not be of value in preventing local recurrences.

Inhibition of peritoneal tumor-cell implantation: model for laparoscopic cancer surgery

A serious concern in applying laparoscopic surgery to malignancies is the possibility of tumor spillage and seeding. We developed a model of peritoneal tumor implantation using a murine bladder tumor cell line, MBT-2. Anesthetized C3H male mice underwent mock laparoscopy with or without peritoneal disruption and instillation of tumor cells via a 16-gauge angiocatheter, and the effect of heparin and the pentapeptide Gly-Arg-Gly-Asp-Ser (GRGDS) on tumor cell adherence and growth was evaluated. Animals were divided into six groups: Group 1 = tumor cells only; Group 2 = peritoneal disruption + tumor cells; Group 3 = heparin + tumor cells; Group 4 = peritoneal disruption + heparin + tumor cells; Group 5 = GRGDS + tumor cells; and Group 6 = peritoneal disruption + GRGDS + tumor cells. In all animals, a greater tumor burden was noted at the sites of peritoneal disruption. Moreover, 50% and 63% of animals in Groups 1 and 2 developed tumors compared with 17% and 31% of those in Groups 3 and 4, respectively. There was significantly more tumor at the sites of peritoneal disruption in the "tumor only" groups than in those that received heparin (mean tumor volume 32.32 mm3 in Group 2 v 2.77 mm3 in Group 4; p < 0.05). The GRGDS-treated groups showed a trend toward decreased number and size of tumors compared with the tumor only groups, although the differences were not statistically significant. These findings imply that prophylactic irrigation with substances that decrease cell adherence may prevent tumor implantation after accidental intraoperative tumor spillage.

Neoplastic seeding of squamous cell carcinoma of the oropharynx

Neoplastic seeding is a concept of mechanical disruption and spread of tumor into normal tissues. It is well-documented and accepted as an explanation for unusual patterns of tumor recurrence at multiple sites in the body. Neoplastic seeding is often invoked as an explanation for stromal recurrences following treatment of laryngeal carcinoma. However, it is impossible to discern whether these recurrences represent peritracheal lymph nodes, persistent or recurrent local disease, or neoplastic seeding of tumor. The purpose of this article is to report two cases of tracheostomy site recurrences after treatment of oropharyngeal squamous carcinoma, in which neoplastic seeding is the most plausible explanation of recurrence. The rarity of this phenomenon appears strikingly small despite significant experimental evidence supporting the possibility of its occurrence. Although specific recommendations for prevention cannot be made, it appears prudent to avoid re-use of instruments that come into direct contact with squamous cell carcinoma tumor surface.

The role of fibronectin in tumor implantation at surgical sites

Fibronectins are a family of glycoproteins with modular functional domains. They mediate cell-cell and cell-matrix interactions which are important in embryogenesis, wound healing, metastasis and other processes. We present data on the influence of fibronectin on wound implantation of a murine mammary carcinoma line, TA3Ha. Fibronectin used in these studies was derived from bovine plasma, human serum, human foreskin fibroblasts, and mouse embryo cultures. TA3Ha cells rarely form tumors in the liver of syngeneic mice when injected intravenously but after hepatic wedge resection, 45% (107/240) of the mice develop tumors in the hepatic wound. Wound implantation is markedly reduced when the cells are pre-exposed to 200 micrograms/ml bovine plasma fibronectin (13%, P = 0.007), human serum fibronectin (0%, P = 0.02), human cellular fibronectin (0%, P = 0.02), or mouse cellular fibronectin (0%, P = 0.04). Lung colonization is also reduced by these fibronectins. These effects are not due to a cytotoxic action of fibronectin, since intraperitoneally injected fibronectin-treated cells form ascites tumor as effectively as do control untreated cells. Local application of a solution containing 0.25 mg/ml mouse cellular fibronectin to the hepatic wound reduces the frequency of tumor implantation from 45% to 5% (1/21, P = 0.001). No tumor implantation inhibition is seen when only suspending medium or albumin in suspending medium is used. The mechanism by which topical application of fibronectin reduces hepatic wound implantation of tumor cells is unclear, but this finding raises an exciting possibility of preventing local recurrence of cancer.

Cell shape changes induced by sulphate in the Cloudman mouse melanoma cell line

The mechanism of cell shape changes and haematogenous translocations (metastases) in mouse malignant melanoma cells induced by phorbol esters and protein kinase C (PKC) is reported as adhesion "downregulation", exocytosis and motility. However, PKC activation also produces intracellular alkalinization, a causal factor in plasma membrane internalization, cell rounding and detachment that does not necessarily implicate specific cell adhesion downregulation. We show here that Cloudman mouse malignant melanoma cells can be induced to round up and detach with concomitant intracellular alkalinization by simple inorganic sulphate treatment, thereby suggesting an alternative explanation to the reported phenomena.

Inhibition of tumor implantation at sites of trauma by Arg-Gly-Asp containing proteins and peptides

We report on the inhibition of wound implantation by TA3Ha mammary carcinoma cells by Arg-Gly-Asp containing proteins and peptides using a hepatic wedge resection model. Intravenously injected TA3Ha cells rarely form tumor in the liver of syngeneic mice, but after hepatic wedge resection, 45% (107/240) of the mice develop tumors in the hepatic wound. Hepatic wound implantation is significantly (P = 0.01) inhibited by pretreating the cells with whole mouse plasma, but not with fibrinogen-depleted plasma or serum. Tumor inhibition is also achieved by pretreatment of cells with fibrinogen (P = 0.05-0.0004), fibronectin (P = 0.007) and laminin, but not by albumin. The active domain appears to be the RGDS sequence since the deca- and tetrapeptides containing RGDS inhibit wound implantation (P less than 0.05). However, the tetrapeptide Arg-Gly-Glu-Ser has no such activity. None of these agents affects ascites tumor formation by the intraperitoneally injected cells, suggesting that anchorage independent growth of cells is not affected. We propose that proteins and peptides containing RGD occupy the binding sites and prevent the cells from interacting with cell adhesion proteins in healing wounds. Proteins and/or peptides containing RGD may be useful for preventing local recurrence in postsurgical cancer patients.

Inhibition of tumor implantation at sites of trauma by plasminogen activators

The authors report on the influence of plasminogen activators (PA) on implantation of TA3Ha mammary tumor cells in the healing hepatic wounds of syngeneic strain A mice. Intravenously injected TA3Ha cells, although they rarely metastasize to the liver, formed tumors in the hepatic wounds of a significant percent (42%, P less than 0.0001) of mice. The frequency of tumor formation declined as the interval between surgery and tumor cell inoculation was increased. Furthermore, preexposure of cells to fibrinogen, fibronectin, laminin, or peptides containing the arginine-glycine-aspartic acid-serine residues dramatically reduced the frequency of tumor formation in the hepatic wounds. These results indicate that TA3Ha cells interact with fibrinogen-related proteins in the wound to aid their attachment and growth. Because these proteins are susceptible to digestion by plasmin, PA were used in this study to examine whether administration of these drugs to the mice would modulate tumor formation in the liver wounds. Among the PA tested, human plasmin B-chain-streptokinase complex (B-SK) and recombinant tissue plasminogen activator (t-PA) inhibited tumor implantation in a dose-related manner. Administration of 900 units (U) of B-SK or 3300 U of t-PA per mouse reduced the frequency of tumor formation from 42% to 0% (P = 0.02) and 11% (P = 0.02), respectively. The B-SK was complexed with p-nitrophenyl-p-guanidinobenzoate; it did not activate the plasminogen or inhibit tumor formation in the hepatic wounds. Although urokinase activated the plasminogen, it did not inhibit tumor implantation in the hepatic wound. Heparin, an anticoagulant that prevents conversion of fibrinogen to fibrin without being fibrinolytic, had no influence on tumor formation in the hepatic wounds. The PA can generate plasmin that digests the cell attachment proteins in wounds and consequently inhibits tumor cell attachment.