Increased expression of the retinoblastoma gene in human colorectal carcinomas relative to normal colonic mucosa.

We report the first evidence of increased levels of the retinoblastoma (Rb) message in a majority of colorectal cancers when compared with normal mucosa. Southern blot analysis showed an increase in Rb gene copy number in at least 28% of colorectal carcinomas relative to normal mucosa. These results plus previous reports of nonrandom chromosome 13 gains in approximately 50% of colorectal cancers suggest that an increase in Rb gene copy number occurs frequently in these tumors. Possible mechanisms pertaining to overexpression of the Rb gene are discussed in relation to its role as a recessive cancer gene.

Frequent loss of heterozygosity on chromosomes 6q, 11, and 17 in human ovarian carcinomas.

Recently, tumor-specific allele loss has been shown to be an important characteristic of some tumors. When such loss includes one or more growth-regulatory genes, it may allow the expression of tumorigenicity. Using Southern blots, we analyzed normal and tumor DNA samples from 19 ovarian cancer patients, using a series of polymorphic DNA probes that map to a variety of chromosomal loci. Of 14 informative cases, tumor-specific allelic loss was observed in nine (64%) at the estrogen receptor (ESR) gene locus on chromosome 6q. On chromosome 17p at the D17S28 and D17S30 loci, allelic losses were also detected in 6 of 8 (75%) and 9 of 14 (64%) cases, respectively. Allelic loss at the HRAS1 gene locus on chromosome 11p occurred in 5 of 11 (46%) informative cases. The relatively high incidence of these allelic losses observed on chromosome 6q represents the first implication by molecular genetic analysis of this chromosomal region in a human malignancy, and it thus appears to be a genetic change specific to ovarian carcinoma. DNA sequence losses on 11p and 17p, also reported for other cancers, may reflect the presence of tumor- or growth-suppressor genes on these chromosomes that are important in the genesis of many tumor types, including ovarian malignancies.

Allele loss at the c-Ha-ras1 locus in human ovarian cancer.

Recent reports have shown allele loss at the c-Ha-ras1 locus on the short arm of chromosome 11 in some types of tumors. To determine whether loss of heterozygosity occurs at the c-Ha-ras1 locus in uncultured human ovarian carcinomas we used Southern blot analysis to study DNA from 17 pairs of ovarian tumors and matched white blood cell samples from the same patients. In one of these 17 tumors, the c-Ha-ras1 locus was rearranged, and in five tumor DNAs from ten informative patients, a c-Ha-ras1 allele was lost. This loss, of relatively high incidence, appears to be an important characteristic of human ovarian cancer and may provide a useful tool for understanding its biological behavior.

Transforming growth factor-alpha production and autoinduction in a colorectal carcinoma cell line (DiFi) with an amplified epidermal growth factor receptor gene.

The DiFi colorectal carcinoma cell line, derived from a patient with familial adenomatous polyposis, was examined for gene expression and production of the autocrine growth factor transforming growth factor alpha (TGF-alpha) and for epidermal growth factor receptor (EGFR) gene expression and gene copy number. DiFi cells expressed TGF-alpha transcripts as identified on Northern (RNA) blots. Addition of TGF-alpha (10 ng/ml) or EGF (10 ng/ml) to DiFi cell cultures (lacking EGF or serum) up-regulated DiFi cell basal TGF-alpha mRNA levels, suggesting that autoinduction of TGF-alpha occurs in these cells. DiFi cell cultures in log phase growth secreted measurable amounts of TGF-alpha (347 pg/10(6) cells/24 h) into their culture medium, as determined by radioimmunoassay. DiFi cells showed strong overexpression of the EGFR gene on Northern blots relative to three other colon cancer cell lines examined. Immunoperoxidase staining showed enhanced EGFR expression in a cell subpopulation among the original (uncultured) ascitic fluid cells from which the DiFi cell line was established. This cell subpopulation was observed to expand dramatically between passages 1 and 25. Immune complex kinase assay of DiFi cells showed that EGFR were functional as determined by their ability to autophosphorylate. The EGFR gene in these cells was not found to be rearranged or genetically altered using Southern blot analysis. Dot blot analysis of DiFi cell DNA revealed EGFR gene amplification in the range of 60-80 copies/cell, which is approximately twice the copy number seen in A-431 epidermoid carcinoma cells. To our knowledge DiFi cells represent the first example of EGFR gene amplification in a colorectal adenocarcinoma. Because DiFi colorectal cancer cells uniquely show production and auto-induction of TGF-alpha in addition to amplification and overexpression of the EGFR gene, these cells represent a valuable tool for studying the role(s) of the EGFR in the regulation of tumor cell growth.

Expression and localization of urokinase-type plasminogen activator in human spinal column tumors.

We have sought to determine the production and activity of serine proteases in primary and metastatic spinal tumors and the association of these enzymes with the invasive and metastatic properties of spinal column tumors. Using immunohistochemical techniques, the cellular localization and expression of urokinase-type plasminogen activator (uPA) was assessed, whereas its activity was determined by fibrin zymography, and the amounts of enzyme were measured by an enzyme-linked immunosorbent assay (ELISA) in primary spinal column tumors (chordoma, chondrosarcoma, and giant cell tumor) and metastatic tumors of the spine arising from various malignancies (breast, lung, thyroid, and renal cell carcinomas, and melanomas). Metastatic tumors displayed higher levels of uPA activity than did primary spinal tumors (P<0.001). Immunohistochemical analysis revealed that uPA expression was highest in metastases from lung and breast carcinomas and melanomas, followed by metastatic tumors from thyroid and renal cell carcinomas. Similar results were obtained for uPA activity and enzyme level as determined by fibrin zymography and ELISA, respectively. We conclude that metastatic spinal tumors possess higher levels of uPA expression and activity than the primary spinal tumors, which tend to be less aggressive and only locally invasive malignancies. The results suggest that the plasminogen system may participate in the metastasis of tumors to the spinal column.

Expression and role of matrix metalloproteinases MMP-2 and MMP-9 in human spinal column tumors.

Matrix metalloproteinases (MMPs) have been implicated in the process of tumor invasion and metastasis formation. Thus, we determined the expression of MMPs in various primary and metastatic spinal tumors in order to assess the role of these enzymes in spinal invasion. MMP expression was examined by immunohistochemical localization, and quantitative evaluation of MMP protein content was determined by enzyme-linked immunosorbant assay (ELISA) and Western blotting. MMP enzyme activity was determined by gelatin zymography. Lung carcinomas and melanomas metastatic to the spine were shown to have higher levels of MMP-9 activity than those of breast, thyroid, renal metastases and primary spinal tumors. Immunohistochemical analysis revealed similar difference in expression of MMP-9 in tissue samples. When the tissue samples were subjected to gelatin zymography for examination of MMP-2 and MMP-9 activity and to ELISA and Western blotting for quantitative estimation of protein content, the most striking results were obtained for lung carcinomas and melanomas relative to the other tumors. Lung carcinomas and melanomas metastatic to the spine had considerably higher levels of MMP-9 activity than those of primary spinal tumor or breast, thyroid, and renal carcinoma metastases. Within the metastatic tumor category, neoplasms that are known to be associated with the shortest overall survival rates and most aggressive behavior, such as lung carcinomas and melanomas, had the highest levels of MMP-2 and MMP-9 activity compared to those less aggressive metastatic tumors such as breast, renal cell, and thyroid carcinomas. Our results suggest that MMPs may contribute to the metastases to the spinal column, and overexpression of these enzymes may correlate with enhanced invasive properties of both primary and metastatic spinal tumors.

Limitations of stereotactic biopsy in the initial management of gliomas.

Stereotactic biopsy is often performed for diagnostic purposes before treating patients whose imaging studies highly suggest glioma. Indications cited for biopsy include diagnosis and/or the "inoperability" of the tumor. This study questions the routine use of stereotactic biopsy in the initial management of gliomas. At The University of Texas M. D. Anderson Cancer Center, we retrospectively reviewed a consecutive series of 81 patients whose imaging studies suggested glioma and who underwent stereotactic biopsy followed by craniotomy/resection (within 60 days) between 1993 and 1998. All relevant clinical and imaging information was reviewed, including computerized volumetric analysis of the tumors based on pre- and postoperative MRI. Stereotactic biopsy was performed at institutions other than M. D. Anderson in 78 (96%) of 81 patients. The majority of tumors were located either in eloquent brain (36 of 81 = 44%) or near-eloquent brain (41 of 81 = 51%), and this frequently was the rationale cited for performing stereotactic biopsy. Gross total resection (>95%) was achieved in 46 (57%) of 81 patients, with a median extent of resection of 96% for this series. Diagnoses based on biopsy or resection in the same patient differed in 40 (49%) of 82 cases. This discrepancy was reduced to 30 (38%) of 80 cases when the biopsy slides were reviewed preoperatively by each of three neuropathologists at M. D. Anderson. Major neurologic complications occurred in 10 (12.3%) of 81 surgical patients and 3 (3.7%) of 81 patients undergoing biopsy. Surgical morbidity was probably higher in our series than it would be for glioma patients in general because our patients represent a highly selected subset of glioma patients whose tumors present a technical challenge to remove. Stereotactic biopsy is frequently inaccurate in providing a correct diagnosis and is associated with additional risk and cost. If stereotactic biopsy is performed, expert neuropathology consultation should be sought.

Molecular genetic studies of colon cancer.

Molecular genetic studies of tumor-specific allele loss, originally associated primarily with research regarding childhood hereditary cancers such as retinoblastoma and Wilms' tumors, only lately have been recognized as a relatively fast and fruitful way of locating cancer genes on human chromosomes. To date, over 25 different cancers have been tied to a gene (or genes) on a specific chromosome when this method has been used. During the past year alone, this approach has permitted detection of three genes involved in either hereditary or sporadic colorectal cancers. These three genes, located on chromosomes 5q, 17p, and 18q, are believed to belong to the newly described tumor suppressor (or growth suppressor) gene class, whose effects are opposite those of activated cellular oncogenes, which promote uncontrolled cell growth. Present studies, however, have not shown losses of any of these tumor suppressor genes to be correlated with the presence of activated ras genes in colorectal adenomas or carcinomas. During progression from adenoma to carcinoma, ras gene mutations and 5q allelic deletions are likely to be earlier events, whereas allelic losses from chromosomes 18q and 17p seem to occur more often in advanced tumors. Involvement of the genes on 5q (FAP) and 18q (Lynch syndrome II) in hereditary colon cancer syndromes is supported by linkage studies, but their respective roles (as well as that of the gene on 17p) in familial and sporadic colorectal cancer remain to be precisely defined. Probable isolation of these three genes by molecular cloning within the next few years will help elucidate their specific biologic functions. It will also permit early detection, and thus prevention, of some familial colon cancers (such as FAP), and possibly allow DNA marker-based separation of different colon cancer subtypes of similar histologic appearance.

Neurosurgical outcomes in a modern series of 400 craniotomies for treatment of parenchymal tumors.

OBJECTIVE: The goals were to critically review all complications resulting within 30 days after craniotomies performed for excision of intra-axial brain tumors relative to factors likely to affect complication rates and to assess the value of these data in predicting the risk of surgical morbidity, particularly for surgery in eloquent brain regions. METHODS: Neurosurgical outcomes were studied for 327 patients who underwent 400 craniotomies for removal of intra-axial parenchymal brain neoplasms in a 21-month period. Tumors removed included gliomas (206 tumors) and metastases (194 tumors) located both supratentorially (358 tumors) and infratentorially (42 tumors). RESULTS: The major complication incidence was 13%, and the operative mortality rate was 1.7%. The overall morbidity rate was 32%, but more types of complications were considered than in previous studies. The major neurological morbidity rate was 8.5%. Based on pre- versus postoperative (at 4 wk) Karnofsky Performance Scale scores, 9% of patients deteriorated neurologically, 32% improved, and 58% showed no change. The median postoperative hospital stay was 5 days. Tumors were defined as Grade I, II, or III based on their location relative to brain function, and this tumor functional grade was the most important variable affecting the incidence of any neurological deficit. Patients with tumors in eloquent (Grade III) or near-eloquent (Grade II) brain areas incurred more neurological deficits than did patients with tumors in noneloquent areas (Grade I). Neither repeat surgery for recurrent disease nor extent of surgical resection affected outcome significantly. Although most tumors in this study, including those in eloquent regions, were removed by gross total resection, this did not lead to more major neurological deficits. Regional complications (at the surgical sites) and systemic complications (medical) were more prevalent among older patients (age >60 yr) with lower preoperative Karnofsky Performance Scale scores (< or = 50) and posterior fossa masses. We showed how our data can be used to predict the total risk of surgical morbidity for a given patient, to facilitate patient counseling and surgical decision-making. CONCLUSION: The finding that gross total resections could be performed in eloquent brain regions with an acceptable level of neurological impairment suggested that the mere presence of a tumor in eloquent brain does not automatically contraindicate surgery. Our results have practical risk-predictive value, and they should aid in the construction of subsequent outcome studies, because we have identified the key areas to monitor.

Total sacrectomy and Galveston L-rod reconstruction for malignant neoplasms. Technical note.

Although radical resection is the best treatment for malignant sacral tumors, total sacrectomy for such tumors has been performed in only a few instances. Total sacral resection requires reconstruction of the pelvic ring plus establishment of a bilateral union between the lumbar spine and iliac bone. This technique is illustrated in two patients harboring large, painful, sacral giant-cell tumors that were unresponsive to prior treatment. These patients were treated with complete en bloc resection of the sacrum and complex iliolumbar reconstruction/stabilization and fusion. Surgery was performed in two stages, the first consisting of a midline celiotomy, dissection of visceral/neural structures, and ligation of internal iliac vessels, followed by an anterior L5-S1 discectomy. The second stage consisted of mobilization of an inferiorly based myocutaneous rectus abdominis pedicle flap for wound closure, followed by an L-5 laminectomy, bilateral L-5 foraminotomy, ligation of the thecal sac, division of sacral nerve roots, and transection of the ilia lateral to the tumor and sacroiliac joints. Placement of the instrumentation required segmental fixation of the lumbar spine from L-3 down by means of pedicle screws and the establishment of a bilateral liaison between the lumbar spine and the ilia by using the Galveston L-rod technique. The pelvic ring was then reestablished by means of a threaded rod connecting left and right ilia. Both autologous (posterior iliac crest) and allograft bone were used for fusion, and a tibial allograft strut was placed between the remaining ilia. The patients were immobilized for 8 weeks postoperatively and underwent progressive rehabilitation. At the 1-year follow-up review, one patient could walk unassisted, and the other ambulated independently using a cane. Both patients controlled bowel function satisfactorily with laxatives and diet and could maintain continence but required self-catheterization for bladder emptying. The authors conclude that in selected patients, total sacrectomy represents an acceptable surgical procedure that can offer not only effective local pain control, but also a potential cure, while preserving satisfactory ambulatory capacity and neurological function.

Coaxial double-lumen methylmethacrylate reconstruction in the anterior cervical and upper thoracic spine after tumor resection.

OBJECT: A unique method of anterior spinal reconstruction after decompressive surgery was used to prevent methylmethacrylate-dural contact in cancer patients who underwent corpectomy. The purpose of this study was to assess the efficacy and stability of polymethylmethacrylate (PMMA) anterior surgical constructs in conjunction with anterior cervical plate stabilization (ACPS) in these patients. METHODS: Approximately 700 patients underwent spinal surgery at The University of Texas M. D. Anderson Cancer Center over a 4-year period. The authors conducted a retrospective outcome study for 29 of these patients who underwent anterior cervical or upper thoracic tumor resections while in the supine position. These patients were all treated using the coaxial, double-lumen, PMMA technique for anterior spinal reconstruction with subsequent ACPS. No postoperative external orthoses were used. Twenty-seven patients (93%) harbored metastatic spinal lesions and two (7%) harbored primary tumors. At 1 month postsurgery, significant improvement was seen in spinal axial pain (p<0.001), radiculopathy (p<0.001), gait (p = 0.008), and Frankel grade (p = 0.002). A total of nine patients (31%) underwent combined anterior-posterior 360 degrees stabilization. Twenty-one patients (72%) experienced no complications. Complications related to instrumentation failure occurred in only two patients (7%). There were no cases in which the patients' status worsened, and there were no neurological complications or infections. The median Kaplan-Meier survival estimate for patients with spinal metastases was 9.5 months. At the end of the study, 13 patients (45%) had died and 16 (55%) were alive. Postoperative magnetic resonance images consistently demonstrated that the dura and PMMA in all patients remained separated. CONCLUSIONS: The anterior, coaxial, double-lumen, PMMA reconstruction technique provides a simple means of spinal cord protection in patients in the supine position while undergoing surgery and offers excellent results in cancer patients who have undergone cervical vertebrectomy.

Chondrosarcoma of the spine: 1954 to 1997.

OBJECT: Primary chondrosarcoma of the spine is extremely rare. During the last 43 years only 21 patients with this disease were registered at The University of Texas M. D. Anderson Cancer Center. The purpose of this study was to examine the demographic characteristics, treatments, and outcomes of this set of patients. METHODS: Medical records for 21 patients were reviewed. Age, sex, race, clinical presentation, tumor histology, tumor location in the spinal column, treatments, surgical details, and response to treatment were recorded. Surgical procedures were categorized as either gross-total resection or subtotal excision of tumor. Neurological function was assessed using Frankel's functional classification. Time to recurrence and survival analyses were performed using the Kaplan-Meier method. The median age of patients was 51 years, with fairly equal gender representation. Eighteen patients underwent at least one surgical procedure for a total of 28 surgical procedures: seven radical resections and 21 subtotal excisions. Radiation therapy was used in conjunction with 10 of the 28 surgical procedures. The median Kaplan-Meier estimate of overall survival for the entire group was 6 years (range 6 months-17 years). Tumors recurred after 18 of the 28 procedures. Kaplan-Meier analysis revealed a statistically significant difference in the per-procedure disease-free interval after gross-total resection relative to subtotal excision (exact log rank 3.39; p = 0.04). The addition of radiation therapy prolonged the median disease-free interval from 16 to 44 months, although this was not statistically significant (exact log rank 2.63; p = 0.16). CONCLUSIONS: Our results suggest that gross-total resection of the chondrosarcoma provides the best chance for prolonging the disease-free interval in patients. Subtotal excision should be avoided whenever possible. Addition of radiation therapy does not appear to lengthen significantly the disease-free interval in this patient population.

Intracranial injection of human meningioma cells in athymic mice: an orthotopic model for meningioma growth.

OBJECT: Although human meningioma cells have been heterotopically implanted in nude mice, introducing these cells into intracranial locations seems more likely to reproduce normal patterns of tumor growth. To provide an orthotopic xenograft model of meningioma, the authors implanted a controlled quantity of meningioma cells at subdural and intracerebral sites in athymic mice. METHODS: Malignant (one tumor), atypical (two tumors), or benign (three tumors) meningiomas were placed into primary cell cultures. Cells (10(6)/10 microl) from these cultures and from an immortalized malignant meningioma cell line, IOMM-Lee, were injected with stereotactic guidance into the frontal white matter or subdural space of athymic mice. Survival curves were plotted for mice receiving tumor cells of each histological type and according to injection site. Other mice were killed at intervals and their heads were sectioned whole. Hematoxylin and eosin staining of these sections revealed the extent of tumor growth. CONCLUSIONS: The median length of survival for mice with malignant, atypical, or benign tumors was 19, 42, or longer than 84 days, respectively. Atypical and malignant tumors were invasive, but did not metastasize extracranially. Malignant tumors uniformly showed leptomeningeal dissemination and those implanted intracerebrally grew locally and spread noncontiguously to the ventricles, choroid plexus, convexities, and skull base. Tumors formed in only 50% of mice injected with benign meningioma cells, whereas injection of more aggressive cells was uniformly successful at tumor production. The three types of human meningiomas grown intracranially in athymic mice maintained their relative positions in the spectrum of malignancy. However, atypical meningiomas became more aggressive after xenografting and acquired malignant features, implying that there had been immune constraint in the original host. Tumor cells injected into brain parenchyma migrated to more optimal environments and grew best there. This model provides insights into the biology of meningiomas and may be useful for testing new therapies.

Transthoracic vertebrectomy for metastatic spinal tumors.

OBJECT: Anterior approaches to the spine for the treatment of spinal tumors have gained acceptance; however, in most published reports, patients with primary, metastatic, or chest wall tumors involving cervical, thoracic, or lumbar regions of the spine are combined. The purpose of this study was to provide a clear perspective of results that can be expected in patients who undergo anterior vertebral body resection, reconstruction, and stabilization for spinal metastases that are limited to the thoracic region. METHODS: Outcome is presented for 72 patients with metastatic spinal tumors who were treated by transthoracic vertebrectomy at The University of Texas M. D. Anderson Cancer Center. The predominant primary tumors included renal cancer in 19 patients, breast cancer in 10, melanoma or sarcoma in 10, and lung cancer in nine patients. The most common presenting symptoms were back pain, which occurred in 90% of patients, and lower-extremity weakness, which occurred in 64% of patients. All patients underwent transthoracic vertebrectomy, decompression, reconstruction with methylmethacrylate, and anterior fixation with locking plate and screw constructs. Supplemental posterior instrumentation was required in seven patients with disease involving the cervicothoracic or thoracolumbar junction, which was causing severe kyphosis. After surgery, pain improved in 60 of 65 patients. This improvement was found to be statistically significant (p < 0.001) based on visual analog scales and narcotic analgesic medication use. Thirty-five of the 46 patients who presented with neurological dysfunction improved significantly (p < 0.001) following the procedure. Thirty-three patients had weakness but could ambulate preoperatively. Seventeen of these 33 regained normal strength, 15 patients continued to have weakness, and one patient was neurologically worse postoperatively. Of the 13 preoperatively nonambulatory patients, 10 could walk after surgery and three were still unable to walk but showed improved motor function. Twenty-one patients had complications ranging from minor atelectasis to pulmonary embolism. The 30-day mortality rate was 3%. The 1-year survival rate for the entire study population was 62%. CONCLUSIONS: These results suggest that transthoracic vertebrectomy and spinal stabilization can improve the quality of life considerably in cancer patients with spinal metastasis by restoring or preserving ambulation and by controlling intractable spinal pain with acceptable rates of morbidity and mortality.

Growth effects of tamoxifen on Lovo colon carcinoma cells and cultured cells from normal colonic mucosa.

The growth effects of tamoxifen (TAM) were studied using normal and malignant colonic epithelial cells. Addition of TAM (0.8 to 10 microM) to cultured normal human colon epithelial cells and Lovo colon adenocarcinoma cells produced a dose response decrease in growth of 42 to 76%. Histamine (1 to 10 microM) did not affect cell growth and did not negate the TAM effect. Calmodulin (2 micrograms/ml) totally blocked growth inhibitory effects of a calmodulin antagonist, trifluoperazine (10 microM), but did not block the TAM inhibitory effect. These data suggest that antiestrogen binding sites (AEBS) may play an important role in the growth-inhibitory effects of TAM on colon cells. Competition with estrogen and antagonism with histamine or calmodulin do not appear to be significant in this regard.

The effects of steroid hormones on a human colon cancer cell line in vitro.

Estrogen analogues, moxestrol (10(-8)-10(-5) M) and ethinyl estradiol (10(-8)-10(-6) M), produced a 30% and 15% inhibition of LoVo cell growth, respectively, in serum-free Ham's F-10 medium. Under the same conditions, no growth effects were observed on these cells following the addition of progesterone or testosterone (10(-8)-10(-6) M); however, metribolone (10(-8)-10(-6) M), a synthetic androgen with glucocorticoid receptor-binding properties, moderately stimulated cell growth (18%). The synthetic antiandrogen, RU 23908 (10(-6) M), did not reduce metribolone effects, and hydrocortisone (10(-9)-10(-7) M) stimulated LoVo cell growth by 31% in serum-free medium. In medium containing 10% charcoal-treated fetal bovine serum, the inhibitory effects of estrogens were not observed, and the lower concentrations (10(-11) M) of moxestrol and ethinyl estradiol facilitated cell growth (10 to 15%). The other steroid hormones produced the same results as observed with serum-free medium. These data suggest that estrogen and glucocorticoid hormones may play an important role in the growth of colon carcinoma cells. Androgen and progesterone hormones appear to be less significant in this regard. Serum factors alter the effects of estrogen, but not of glucocorticoids.

Expression of the gene coding for the light chain of calpactin I (annexin II) in cell lines DiFi, HT-29, and WI-38.

Calpactin I (annexin II) light chain gene messages were expressed in the DiFi and HT-29 human colon cancer cell lines, as well as in the diploid lung fibroblast cell line WI-38. However, expression of an approximately 1.0 kb transcript was stronger in DiFi and HT-29 cells than in WI-38 cells. The moderate to strong expression of such transcripts in DiFi and HT-29 cells indicates that the calcium binding protein, calpactin I, may be abundant in colon carcinoma cells. Calpactin I is the major substrate of pp60v-src, a tyrosine-specific protein kinase encoded by v-src, whose cellular homologue c-src also codes for a tyrosine kinase (pp60c-src), known to be activated in colon carcinomas and in cell lines derived from them (including HT-29). Abundance of calpactin I in such cells is consistent with the possibility that activation of the pp60c-src tyrosine kinase contributes to the origin of human colon cancers.

A study of chromosome 6 allele loss in human colorectal carcinomas.

Matched normal/tumor DNA pairs from patients with sporadic and hereditary (FAP = familial adenomatous polyposis) colorectal carcinoma were examined for tumor-specific allele loss on chromosome 6 using cDNA probes for the avian myeloblastosis viral oncogene homologue (MYB on 6q22-q23), the estrogen receptor (ESR on 6q24-q27), and for the alpha polypeptide of human chorionic gonadotropin (CGA on 6q14-q21). No chromosome 6 allele loss was observed at these gene loci among 22 colorectal carcinomas examined, although such losses were relatively frequent (37.5% of informative individuals) at the D17S28 locus on chromosome 17. These results are consistent with karyological studies and indicate that chromosome 6 allele loss from colorectal carcinomas may occur less frequently than previously reported.

Analysis of the estrogen receptor gene structure in human breast cancer.

We studied the structure of the human estrogen receptor (ER) gene by Southern blot analysis in 34 tumor samples and normal breast tissues or peripheral blood samples from the same patients. No rearrangement or amplification of the ER gene was seen in either ER-positive or ER-negative breast tumors. One patient showed an apparent constitutional deletion of a non-allelic ("invariant") restriction fragment in DNAs from both normal leukocytes and bilateral breast tumors. Of 20 patients constitutionally heterozygous for an ER gene RFLP, only one showed tumor-specific loss of heterozygosity. This is consistent with the ER gene change we noted overall. At the c-myb locus on chromosome 6q adjacent to the ER gene, allele loss occurred in 1 out of 15 informative cases. In addition, tumor-specific allelic loss at the c-H-ras1 locus on chromosome 11p occurred in 4 of 22 informative cases, and at the D17S28 locus on chromosome 17p in 2 of 7 informative cases.

The role of vitamin D3 in the proliferation of a human colon cancer cell line in vitro.

LoVo, a cultured colon cancer cell line, is shown to possess a receptor for 1,25-dihydroxy vitamin D3 (1 alpha,25(OH)2D3) with a low capacity (28 fmol/mg protein) and high affinity (Kd: 1.9 x 10(-21)0M). When these cells were grown in monolayer culture in a chemically defined serum-free medium, a significant inhibition of proliferation was seen in the presence of 10 nM to 1 microM of 1 alpha,25(OH)2D3 (p less than 0.005. Furthermore, 1 alpha,25(OH)2D3 delayed early attachment of cells. After 8 days of treatment, aggregated cuboidal cells showed a marked change to an apparently spindle like morphology. The 1 alpha,25(OH)2D3 growth-inhibitory effect was modulated by verapamil (1 microM), a calcium channel blocker, hydrocortisone (1 microM), and moxestrol (1 mM), an estrogen analogue, and 2% charcoal-treated fetal bovine serum. This study represents the first demonstration of 1 alpha,25(OH)2D3 modulation of growth of human colon cells.