Effect of tamoxifen on 1,2-dimethylhydrazine-HCl-induced colon carcinogenesis in rats

BACKGROUND

Evidence suggests that steroid hormones may affect the natural history of colon cancer.

METHODS

Baseline levels of estrogen receptors, polyamines, and ornithine decarboxylase in colonic mucosa, and blood estradiol were measured in 10 normal Sprague-Dawley outbread female rats. Therefore, 151 rats were fed a 15% fat diet and divided into three groups. Rats in the control group (n = 20) received weekly s.c injections of the 1,2-Dimethylhydrazine-HCl (DMH) vehicle. To induce colon cancer, 131 rats received weekly subcutaneous injections of DMH (20 mg/kg). Of these 131 rats, 65 also ingested 0.5 microgram/g tamoxifen, daily. Half of the rats in each group were sacrificed at 14 weeks, the remainder at 28 weeks. All measurements were repeated at these times and tumor incidence was calculated.

RESULTS

The number of rats with tumors was 41% higher (P = .07) in rats treated with DMH vs those treated with tamoxifen and DMH (72.7% vs 51.5%). Tumor cells in both groups had higher levels of polyamines and ornithine decarboxylase activities (P = .03 to P < .001) and lower levels of estrogen receptors (P = .005) to P < .001) compared to adjacent normal colonic mucosa. Estrogen receptors were not detected in the colons of the rats in the control group. No correlations were found between estradiol and estrogen receptors in normal (r = .01, P = .95) or tumor (r = .03, P = .86) cells, or between polyamines or ornithine decarboxylase and estrogen receptors in normal (r = .01 to .14, P = .63 to .95) or tumor (r = .07 to .26, P = .16 to .86) cells.

CONCLUSIONS

Tamoxifen reduced the incidence of DMH-induced colon cancer in rats and may thus have chemopreventive effects. Although it was not statistically significant, further studies are justified to continue this line of research.

Ataxia-telangiectasia: founder effect among north African Jews

The ATM gene is responsible for the autosomal recessive disorder ataxia-telangiectasia (A-T), characterized by cerebellar degeneration, immunodeficiency and cancer predisposition. A-T carriers were reported to be moderately cancer-prone. A wide variety of A-T mutations, most of which are unique to single families, were identified in various ethnic groups, precluding carrier screening with mutation-specific assays. However, a single mutation was observed in 32/33 defective ATM alleles in Jewish A-T families of North African origin, coming from various regions of Morocco and Tunisia. This mutation, 103C-->T, results in a stop codon at position 35 of the ATM protein. In keeping with the nature of this mutation, various antibodies directed against the ATM protein failed to defect this protein in patient cells. A rapid carrier detection assay detected this mutation in three out of 488 ATM alleles of Jewish Moroccan or Tunisian origin. This founder effect provides a unique opportunity for population-based screening for A-T carriers in a large Jewish community.

Results after restorative proctocolectomy and ileal pouch-anal anastomosis in patients with familial adenomatous polyposis and coexisting colorectal cancer

Although the operation of choice for patients with familial adenomatous polyposis (FAP) is restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA), its place in the management of patients with FAP and cancer has not been defined. The authors have reviewed their experience with these patients to determine the safety of IPAA and its efficacy as a cancer operation. The records of 55 patients with FAP who had undergone IPAA were examined. Follow-up studies included an annual questionnaire and physical examination. Eight patients had FAP with coexisting colorectal cancer. Median age at diagnosis was 25 (range 13-46) years, and at operation 33 (range 22-36) years. Of the eight patients (four men), four had colonic cancer and four had rectal cancer. Synchronous colorectal carcinoma was found in two patients. Staging according to the tumor node metastasis classification showed that five patients had stage 1 tumour, two had stage 2 and one had stage 3. Tumours were well, moderately or poorly differentiated in one, five and two patients respectively. During a median follow-up of 56 (range 14-98) months, metastasis developed in the liver of one patient 66 months after surgery. Two patients suffered complications: one had small bowel obstruction and the other mucosal prolapse. Tubular adenomas were found in the pouch of two patients and in the anal transitional zone of one. Pouch function is good to excellent in all surviving patients. Restorative proctocolectomy for patients with FAP and coexisting colorectal cancer can be undertaken with a favourable prognosis and function. It is compatible with curative intent.

The effect of tamoxifen on established human colorectal cancer cell lines in vitro

The purpose of this study was to evaluate the effect of the anti-estrogenic tamoxifen (Tx) on the growth of human colorectal cancer cells.

METHODS

Serial concentrations (0.005 microM, 0.05 microM, 0.5 microM, 5 microM, and 50 microM) of the anti-estrogenic tamoxifen (Tx) were added and analyzed for their effect on the growth of established human colorectal cancer cells. HT-29 and SW-620 colon cancer cells and SW-1463 rectal cancer cells were tested in both serum-free media and serum-containing media (10% fetal calf serum). COLO-205 colon cancer and SW-837 rectal cancer cells were only tested in 10% fetal calf serum-containing media. Cell growth was measured with the hexosaminidase assay and was compared among the different groups. Cells were analyzed for estrogen receptors using enzyme immunoassay.

RESULTS

In serum-free media, Tx inhibited the growth of HT-29 (P = .05) and SW-620 (P = .01) colon cancer cells at all concentrations tested.

RESULTS

In serum-containing media, Tx inhibited (P = .04) the growth of the SW-837 rectal cancer cells at all concentrations and SW-1463 (P = .05) rectal cancer cells at the concentrations of 0.05 microM and 0.5 microM Tx. The inhibition of cell growth in HT-29, SW-620 and SW-1463 line was greater (P < .001) under serum-free media conditions. Estrogen receptors were not detected in any of the cell lines tested.

CONCLUSIONS

Hormonal manipulation with colo-rectal cancers is possible, but the effect of Tx on the growth of colon cancer cells differs from the effect on rectal cancer cells under various conditions. The mechanism of inhibition is not clear yet, and further studies are warranted before any clinical implications can be postulated.

Identification and chromosomal localization of Atm, the mouse homolog of the ataxia-telangiectasia gene

Atm, the mouse homolog of the human ATM gene defective in ataxia-telangiectasia (A-T), has been identified. The entire coding sequence of the Atm transcript was cloned and found to contain an open reading frame encoding a protein of 3066 amino acids with 84% overall identity and 91% similarity to the human ATM protein. Variable levels of expression of Atm were observed in different tissues. Fluorescence in situ hybridization and linkage analysis located the Atm gene on mouse chromosome 9, band 9C, in a region homologous to the ATM region on human chromosome 11q22-q23.

Effect of systemic steroids on ileal pouch-anal anastomosis in patients with ulcerative colitis

BACKGROUND

Long-term steroid therapy predisposes to postsurgical complications, especially in patients with inflammatory bowel disease.

PURPOSE

This study was undertaken to determine incidence of early septic complications after ileal pouch-anal anastomosis (IPAA) in patients who are undergoing prolonged steroid therapy.

METHODS

We reviewed charts of 692 patients undergoing restorative proctocolectomy and IPAA to treat ulcerative colitis. Incidence of early (within 30 days) septic complications and sepsis-related reoperations, in patients who were having high-dose (>20 mg of prednisone per day) and low-dose steroid therapy (<20 mg of prednisone per day) for more than one month before surgery, was compared with patients who were not receiving steroid therapy. Follow-up included an annual questionnaire and physical examination.

RESULTS

Patients without steroid dose data recorded were excluded (n = 21). Of the 671 remaining patients, 310 received no steroids, 169 received low-dose steroids, and 192 received high-dose steroids. These three groups were similar in gender composition, age at surgery, types of anastomosis (stapled or handsewn), and incidence of diabetes mellitus, peripheral vascular disease, and obesity. Early septic complications were found in 18 (6 percent), 14 (8 percent), and 12 (6 percent) patients without steroid therapy, those having low-dose steroid therapy, and those having high-dose steroid therapy (P = 0.57), respectively. Sepsis- related reoperation rate (P = 0.73) and number of sepsis-related pouch excisions (P = 0.79) did not differ between groups. In patients undergoing IPAA without ileostomy, early septic complications were found in one (3.8 percent), two (20 percent), and five (50 percent) patients without steroid treatment, low-dose steroid therapy, and high-dose steroid therapy (P = 0.004), respectively.

CONCLUSION

In patients who are undergoing IPAA with diversion for ulcerative colitis, prolonged systemic steroid therapy before surgery is not associated with increased septic complications.

A human gene (DDX10) encoding a putative DEAD-box RNA helicase at 11q22-q23

A human gene encoding a putative RNA helicase, designated DDX10, was identified 400 kb telomeric to the ataxia-telangiectasia gene at chromosome 11q22-q23. The predicted amino acid sequence shows very high similarity to a subgroup of DEAD-box RNA helicases involved in ribosome biogenesis. This novel gene encodes a 3.2-kb transcript in a variety of human tissues. A processed pseudogene of DDX10 was detected at chromosome 9q21-q22. We observed a rare trinucleotide repeat length polymorphism within the coding sequence of DDX10.

Genomic Organization of the ATM gene

The ATM gene was recently identified and found to be responsible for the genetic disorder ataxiatelgiectasia. The major ATM transcript is 13 kb. Using long-distance PCR, we determined the genomic structure of this gene and identified all of its exon-intron boundaries. The ATM gene spans approximately 150 kb of genomic DNA and consists of 66 exons. The initiation codon falls within exon 4. The last exon is 3.8 kb and contains the stop codon and a 3'-untranslated region of about 3600 nucleotides.

Predominance of null mutations in ataxia-telangiectasia

Ataxia-telangiectasia (A-T) is an autosomal recessive disorder involving cerebellar degeneration, immunodeficiency, chromosomal instability, radiosensitivity and cancer predisposition. The responsible gene, ATM, was recently identified by positional cloning and found to encode a putative 350 kDa protein with a Pl 3-kinase-like domain, presumably involved in mediating cell cycle arrest in response to radiation-induced DNA damage. The nature and location of A-T mutations should provide insight into the function of the ATM protein and the molecular basis of this pleiotropic disease. Of 44 A-T mutations identified by us to date, 39 (89%) are expected to inactivate the ATM protein by truncating it, by abolishing correct initiation or termination of translation, or by deleting large segments. Additional mutations are four smaller in-frame deletions and insertions, and one substitution of a highly conserved amino acid at the Pl 3-kinase domain. The emerging profile of mutations causing A-T is thus dominated by those expected to completely inactivate the ATM protein. ATM mutations with milder effects may result in phenotypes related, but not identical, to A-T.

Stapled ileal pouch anal anastomoses are safer than handsewn anastomoses in patients with ulcerative colitis

BACKGROUND

One of the theoretic advantages of using a stapled versus handsewn ileal pouch anal anastomosis (IPAA) in restorative proctocolectomy is a reduction in septic complications. We performed this study to compare the incidence of early septic complications in patients undergoing restorative proctocolectomy with stapled or handsewn IPAA.

PATIENTS AND METHODS

A chart review of 692 patients undergoing restorative proctocolectomy for treatment of ulcerative colitis was performed. The incidence of early septic complications in patients having stapled IPAA was compared to that in patients having handsewn IPAA. Follow-up studies included an annual questionnaire and physical examination.

RESULTS

Of the 692 patients, 238 had handsewn IPAA and 454 had stapled IPAA; these two groups were similar in sex, duration of disease, age at surgery, and type of surgical procedure performed. In the handsewn IPAA group, 25 patients (10.5%) had 32 septic complications, and 24 required 89 reparations. In 7 patients, the pouch was excised. In the stapled IPAA group, 21 patients (4.6%) had 23 septic complications, and 14 required 40 reparations. One patient needed pouch excision. There were more patients (P=0.0001) with early septic complications, and more (P<0.0001) pouch excisions because of these complications, in patients with handsewn IPAA than in patients with stapled IPAA. The sepsis-related reoperation rates did not differ significantly.

CONCLUSIONS

The stapled technique for IPAA has fewer septic complications and results in fewer sepsis-related pouch excisions, in our hands, than the handsewn technique technique, for treating patients with ulcerative colitis.

The complete sequence of the coding region of the ATM gene reveals similarity to cell cycle regulators in different species

Ataxia-telangiectasia (A-T) is an autosomal recessive disorder involving cerebellar degeneration, immunodeficiency radiation sensitivity, and cancer predisposition. A-T heterozygotes are moderately cancer prone. The A-T gene, designated ATM, was recently identified in our laboratory by positional cloning, and a partial cDNA clone was found to encode a polypeptide with a PI-3 kinase domain. We report here the molecular cloning of a cDNA contig spanning the complete open reading frame of the ATM gene. The predicted protein of 3056 amino acids shows significant sequence similarities to several large proteins in yeast, Drosophila and mammals, all of which share the PI-3 kinase domain. Many of these proteins are involved in the detection of DNA damage and the control of cell cycle progression. Mutations in their genes confer a variety of phenotypes with features similar to those observed in human A-T cells. The complete sequence of the ATM gene product provides useful clues to the function of this protein, and furthers understanding of the pleiotropic nature of the A-T mutations.

Ileal pouch-anal anastomoses complications and function in 1005 patients

BACKGROUND

Restorative proctocolectomy and ileal pouch-anal anastomosis (IPAA) has become an established surgery for patients with chronic ulcerative colitis and familial adenomatous polyposis.

PURPOSE

The authors report the results of an 11-year experience of restorative proctocolectomy and IPAA at a tertiary referral center.

METHODS

Chart review was performed for 1005 patients undergoing IPAA from 1983 through 1993. Preoperative histopathologic diagnoses were ulcerative colitis (n = 858), familial adenomatous polyposis (n = 62), indeterminate colitis (n = 75), and miscellaneous (n = 10). Information was obtained regarding patient demographics, type and duration of diseases, previous operations, and indications for surgery. Data were collected on surgical procedure and postoperative pathologic diagnosis. Early (within 30 days after surgery) and late complications were noted. Follow-up included an annual function and quality-of-life questionnaire, physical examination, and biopsies of the pouch and anal transitional zone.

RESULTS

Of the 1005 patients (455 women), postoperative histopathologic diagnoses were as follows: ulcerative colitis (n = 812), familial adenomatous polyposis (n = 62), indeterminate colitis (n = 54), Crohn's disease (n = 67), and miscellaneous (n = 10). During a mean follow-up time of 35 months (range 1-125 months), histopathologic diagnoses were changed for 25 patients. The overall mortality rate was 1% (n = 10 patients, early = 4, late = 6); one death (0.1%) was related to pouch necrosis and sepsis. The overall morbidity rate was 62.7% (1218 complications in 630 patients; early, n = 27.5%; late, n = 50.5%). Septic complication and reoperation rates were 6.8% and 24%, respectively. The ileal pouch was removed in 34 patients (3.4%), and it is nonfunctional in 11 (1%). Functional results and quality of life were good to excellent in 93% of the patients with complete data (n = 645) and are similar for patients with ulcerative colitis, familial adenomatous polyposis, indeterminate colitis, and Crohn's disease. Patients who underwent operations from 1983 through 1988 have similar functional results and quality of life compared with patients who underwent operations after 1988.

CONCLUSION

Restorative proctocolectomy with an IPAA is a safe procedure, with low mortality and major morbidity rates. Although total morbidity rate is appreciable, functional results generally are good and patient satisfaction is high.

Anal canal inflammation after ileal pouch-anal anastomosis. The need for treatment

One technique used during restorative proctocolectomy to prevent loss of continence involves preservation of the anal canal. This technique retains a small amount of colonic mucosa and transitional mucosa that may become inflamed or develop dysplastic or neoplastic changes.

PURPOSE

This study was designed to determine the presence and severity of anal canal inflammation and the need for treatment.

METHOD

Records of 217 patients with mucosal ulcerative colitis who underwent restorative proctocolectomy with a stapled ileal pouch-anal anastomosis without anal mucosectomy from 1987 through 1990 were retrospectively reviewed.

RESULTS

Anal canal inflammation was evident on both endoscopy and biopsy in 48 patients (22.11 percent); 18 patients (8.29 percent) had a normal ileal pouch (9 had symptoms; 5 required topical treatment), and 30 patients (13.82 percent) had associated ileal pouch inflammation (23 with symptoms requiring systemic treatment because of pouchitis; 10 patients had concomitant topical treatment).

CONCLUSION

Symptomatic inflammation of the retained mucosa occurred in 32 (14.7 percent) patients. Nine (4.1 percent) patients had inflammation of the anal canal alone, and 23 (10.6 percent) had pouchitis in addition. The need for treatment occurred in 28 (12.9 percent) of the total ((2.3 percent) patients with anal canal inflammation and 23 (10.6 percent) with anal canal inflammation plus pouchitis).

A single ataxia telangiectasia gene with a product similar to PI-3 kinase

A gene, ATM, that is mutated in the autosomal recessive disorder ataxia telangiectasia (AT) was identified by positional cloning on chromosome 11q22-23. AT is characterized by cerebellar degeneration, immunodeficiency, chromosomal instability, cancer predisposition, radiation sensitivity, and cell cycle abnormalities. The disease is genetically heterogeneous, with four complementation groups that have been suspected to represent different genes. ATM, which has a transcript of 12 kilobases, was found to be mutated in AT patients from all complementation groups, indicating that it is probably the sole gene responsible for this disorder. A partial ATM complementary DNA clone of 5.9 kilobases encoded a putative protein that is similar to several yeast and mammalian phosphatidylinositol-3' kinases that are involved in mitogenic signal transduction, meiotic recombination, and cell cycle control. The discovery of ATM should enhance understanding of AT and related syndromes and may allow the identification of AT heterozygotes, who are at increased risk of cancer.

Safety of urgent restorative proctocolectomy with ileal pouch-anal anastomosis for fulminant colitis

PURPOSE

Subtotal colectomy with ileostomy is the operation of choice for patients with fulminant colitis. Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis (IPAA) is preferred for patients who undergo elective surgery for ulcerative colitis. We retrospectively evaluated the safety of RPC with IPAA in patients with a moderate form of fulminant colitis.

METHODS

A chart review of 737 patients who underwent RPC with IPAA for ulcerative and indeterminate colitis from 1983 through 1992 was performed. Moderate fulminant colitis was defined as acute disease requiring hospitalization and parenteral steroid therapy, but without hypotension (systolic blood pressure, < 100 mmHg), tachycardia (> 120 beats/min), or megacolon.

RESULTS

Twelve patients with moderate fulminant colitis underwent urgent surgery (1.6 percent). They had been treated preoperatively for 5.1 +/- 2.3 days with intravenous high-dose steroids, total parenteral nutrition, and antibiotics. These patients had a shorter length of disease (P = 0.01), lower hemoglobin, hematocrit, and albumin (P = 0.001), and higher temperature (P = 0.002) and leukocyte count (P = 0.007) than patients undergoing elective surgery. No early septic complications occurred, although perianal abscess occurred in one patient and pouch-anal fistula in another patient, 13 and 14 months after surgery, respectively.

CONCLUSION

In carefully selected, hemodynamically stable patients with fulminant colitis and without megacolon, RPC with IPAA can be safely performed.

A high-density microsatellite map of the ataxia-telangiectasia locus

The locus of the autosomal recessive disorder ataxia-telangiectasia (A-T) has been assigned by linkage analysis with biallelic markers to a 4-Mb interval on chromosome 11q22-23, between GRIA4 and D11S1897. We have undertaken to saturate the A-T region with highly polymorphic microsatellite markers. To this end, we have identified seven new polymorphic CA-repeats in this region, and have mapped to it five new markers generated by Genethon and the Cooperative Human Linkage Center. These markers are in addition to 12 others that we have previously mapped or generated at the A-T locus. All 24 markers have been integrated into a high-density microsatellite map spanning some 6 Mb DNA. This map, which contains the A-T locus and flanking sequences, allows the construction of extensive, highly informative haplotypes.

Human cDNA clones that modify radiomimetic sensitivity of ataxia-telangiectasia (group A) cells

Genes responsible for genetic diseases with increased sensitivity to DNA-damaging agents can be identified using complementation cloning. This strategy is based on in vitro complementation of the cellular sensitivity by gene transfer. Ataxia-telangiectasia (A-T) is a multisystem autosomal recessive disorder involving cellular sensitivity to ionizing radiation and radiomimetic drugs. A-T is genetically heterogeneous, with four complementation groups. We attempted to identify cDNA clones that modify the radiomimetic sensitivity of A-T cells assigned to complementation group [A-T(A)]. The cells were transfected with human cDNA libraries cloned in episomal vectors, and various protocols of radiomimetic selection were applied. Thirteen cDNAs rescued from survivor cells were found to confer various degrees of radiomimetic resistance to A-T(A) cells upon repeated introduction, and one of them also partially influenced another feature of the A-T phenotype, radioresistant DNA synthesis. None of the clones mapped to the A-T locus on chromosome 11q22-23. Nine of the clones were derived from known genes, some of which are involved in cellular stress responses. We concluded that a number of different genes, not necessarily associated with A-T, can influence the response of A-T cells to radiomimetic drugs, and hence the complementation cloning approach may be less applicable to A-T than to other diseases involving abnormal processing of DNA damage.

Ataxia telangiectasia and lymphoma: an indication for individualized chemotherapy dosing--report of treatment in a highly inbred Arab family

Ten of 18 children in a highly inbred Arab kindred suffered from either ataxia telangiectasia (AT) or a variant syndrome consisting of ataxia, microcephaly, and congenital cataract (AMC). Four of the nine afflicted children were treated in our unit when they developed lymphomas (both Hodgkin's and non-Hodgkin's including Burkitt's). They were given chemotherapy (either standard COMP or low-dose ABV/CVPP). The children with non-Hodgkin's lymphomas died of sepsis after receiving full-dose COMP. Low-dose ABV/CVPP brought about a 20-month remission in one child with nodular sclerosing Hodgkin's lymphoma and both AT and AMC, but she developed a preleukemic syndrome and her parents refused further treatment; she too died. A fourth child, also with nodular sclerosing Hodgkin's lymphoma, is currently in complete remission after ABV/CVPP. Treatment of lymphomas in patients with AT is extraordinarily difficult and has potential side effects so grave as to necessitate careful monitoring and individualized protocols.

Surgery for the teenager with familial adenomatous polyposis: ileo-rectal anastomosis or restorative proctocolectomy?

Increasing numbers of polyposis registries have led to more young patients being diagnosed with familial adenomatous polyposis (FAP). To provide guidelines for selecting the appropriate surgical procedure in teenagers (10-19 years), we compared the results of colectomy and ileo-rectal anastomosis (IRA, n = 17 patients) to the results of restorative proctocolectomy and ileal pouch-anal anastomosis (IPAA, n = 7 patients). Charts were reviewed to obtain data on the operative technique, blood loss and transfusions, hospital stay (including the time for ileostomy closure), and early (within 30 days of surgery) and late complications. Functional results (bowel movements per 24 h, use of antidiarrheal drugs, seepage, and fecal incontinence) and quality of life were evaluated prospectively with a questionnaire and physical examination. The median follow-up time was 49 months (range, 6 to 95 months) after IRA, and 36 months after IPAA (range, 4 to 87 months). Although restorative proctocolectomy and IPAA, is a longer (5.75 vs 3.1 hours), more bloody (500 vs 300 mL blood loss), and more complex operation with a longer hospital stay (12 vs 7 days) than IRA (P = 0.008, P = 0.006, P = 0.02, respectively), no significant difference (P > 0.05) was found between groups concerning the complication rate or quality of life. For teenagers with FAP and rectal carpeting, large rectal adenomas, curable cancer in the upper two-thirds of the rectum, or who are unavailable for follow-up, we recommend a restorative proctocolectomy and IPAA. For the other patients, the decision whether to perform IRA or restorative proctocolectomy with IPAA depends on the patient's desire and the surgeon's skill.

Incidence, risk factors, and treatment of dysplasia in the anal transitional zone after ileal pouch-anal anastomosis

Preservation of the anal transitional zone (ATZ) after restorative proctocolectomy and stapled ileal pouch-anal anastomosis (IPAA) for ulcerative colitis is controversial.

PURPOSE

To evaluate the incidence, risk factors, and treatment options for dysplasia and/or cancer after restorative proctocolectomy and stapled IPAA.

METHODS

We reviewed the records of all 254 patients operated on for ulcerative colitis who had a restorative proctocolectomy, stapled IPAA, and annual postoperative biopsies of ATZ. Follow-up studies included an annual questionnaire and physical examination.

RESULTS

During a follow-up of 2.3 +/- 1.4 (mean +/- standard deviation) years, low-grade dysplasia was found in eight patients (3.1 percent), 16 (median: range, 6-56) months after surgery. Repeated biopsies revealed dysplasia in only two of eight patients, and completion mucosectomy was performed. Dysplasia in ATZ was associated with a preoperative (P = 0.02) or postoperative (P = 0.04) pathologic diagnosis of ulcerative colitis with concurrent dysplasia or cancer. No association (P > 0.05) was found between dysplasia and the following: age, sex, preoperative length of disease, use of a double-stapled versus single-stapled technique, or anastomotic distance from the dentate line.

CONCLUSIONS

Incidence of low-grade dysplasia in ATZ was low. Restorative proctocolectomy with total mucosectomy of the anal canal and handsewn IPAA is recommended for patients with preoperative diagnosis of ulcerative colitis and concurrent cancer or dysplasia. Frequent follow-up with biopsies is recommended for patients with incidental finding of cancer or high-grade dysplasia after restorative proctocolectomy and stapled IPAA with preservation of ATZ. For persistent or recurrent low-grade dysplasia, we recommend a completion mucosectomy.

Physical and genetic mapping at the ATA/ATC locus on chromosome 11q22-23

Genetic heterogeneity in ataxia-telangiectasia (A-T) points to four different genes responsible for this disease. The two major A-T genes, ATA and ATC, were localized by genetic analysis close to each other on chromosome 11q22-23, prompting efforts of positional cloning. Essential steps in positional cloning are long-range cloning of the genomic region of interest, and derivation of highly polymorphic markers that would allow further reduction of the interval carrying the A-T gene. We constructed genomic contigs across the D11S611-D1S424 region harbouring the ATA and ATC genes in yeast artificial chromosome (YAC) vectors. These contigs were used as a fine mapping tool and enabled us to localize along the A-T region, eight microsatellite markers generated randomly by genome mapping centres. In addition, we used specific YAC clones to generate five new microsatellite markers based on polymorphic CA repeats. Recombination mapping based on Israeli A-T families indicates that the ATC gene is distal to the locus D11S1817. Further linkage analysis using these markers is expected to reduce the major A-T locus considerably to a size appropriate for cosmid cloning and identification of transcribed sequences.

A YAC contig spanning the ataxia-telangiectasia locus (groups A and C) at 11q22-q23

Ataxia-telangiectasia (A-T) is an autosomal recessive disease involving cerebellar degeneration, immunodeficiency, cancer predisposition, chromosomal instability and radiosensitivity. A-T is heterogeneous, and the majority of A-T cases are associated with two complementation groups, A and C. The ATA and ATC loci are closely linked at chromosome 11q22-q23. Recombination mapping and linkage disequilibrium analysis have confined both loci between the markers D11S1817 and D11S927, spaced approximately 3.5 Mb apart. Isolation in yeast artificial chromosomes of the genomic segment defined by these loci is essential to identify the gene or genes containing the ATA and ATC mutations. A YAC contig spanning 4.5 Mb, which includes the D11S1817-D11S927 interval, was constructed using two whole genome libraries (ICRF and St. Louis), and a chromosome 11-specific library. Construction of this contig was expedited by prior generation of a region-specific ICRF sublibrary using Alu-PCR products derived from a radiation hybrid. The contig was expanded further by screening the libraries with Alu-PCR products derived from YAC clones and with STSs from YAC ends. YAC clones were aligned by fingerprinting with moderately repetitive probes.

Ulcerative colitis and coexisting colorectal cancer: recurrence rate after restorative proctocolectomy

BACKGROUND

The association between mucosal ulcerative colitis (MUC) and adenocarcinoma is well established.

METHODS

Records of patients who had undergone restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) from 1983 through 1992 were examined. Of these, 604 had MUC and 27 (4.3%) had MUC with coexisting cancer. Patients were surveyed annually for recurrent disease. Pouch function and quality of life were evaluated with a questionnaire and physical examination.

RESULTS

The duration of disease was longer (p = 0.001) in patients with cancer (16.1 +/- 8.0 years) than in those without cancer (9.1 +/- 7.1 years), although the mean age at diagnosis of MUC was the same. Of the 27 patients, 20 had colon cancer and seven had rectal cancer. Multicentricity was found in seven (25.9%) patients. Using the TNM staging classification, 14 patients (51.8%) had stage 1 cancer, eight (29.6%) had stage 2, four (14.8%) had stage 3, and one (3.8%) had stage 4. The patient with stage 4 cancer died 5 months after surgery and was excluded from the follow-up analysis. During a mean follow-up time of 4.3 +/- 2.6 years, cancer recurred in two of the remaining 26 patients (7.7%). In one patient, a local recurrence was found 8 months after surgery, and distant metastases were found in the other patient 35 months after surgery. Both recurrences were in patients with colon cancer. Two of the 26 patients died; one death was related to cancer recurrence (3.8%). Pouch function is good to excellent in all surviving patients.

CONCLUSIONS

Restorative proctocolectomy for patients with MUC and coexisting colorectal cancer can be performed with a favorable prognosis and function. It is appropriate for curative intent, given that an adequate margin without tumor is obtained.

The effect of tamoxifen and fenretinimide on human colorectal cancer cell lines in vitro

BACKGROUND

The natural history of colorectal neoplasia may be influenced by steroid hormones and nutritional compounds. We evaluated the effect of the anti-estrogenic tamoxifen (Tx), and the synthetic retinoid fenretinimide (4-HPR) on the growth of human colorectal cancer cells.

METHODS

DLD-1, CACO-2, SW-620, and COLO-205 colon cancer cells, and SW-1463 and SW-837 rectal cancer cells were cultured under serum-free conditions. Quadruplicates wells (4 x 10(4) cells/well) were created for each treated, and untreated groups in each cell line. Cells were treated with 1 microM Tx, 5 microM Tx, 1 microM 4-HPR, 1 microM Tx with 1 microM 4-HPR, and 5 microM Tx with microM 4-HPR. Cell growth was measured colorimetrically with the hexosaminidase assay (405 nm), and was compared among the different groups. Cells were analyzed for estrogen receptors using an enzyme immunoassay.

RESULTS

Tamoxifen, 4-HPR, or both, inhibited the growth in DLD-1 (P = .001), COLO-205 (P = .02), SW-620 (P = .001), and CACO-2 (P = .02) cell lines. Tamoxifen with 4-HPR inhibited cell growth more (P = .03) than did either Tx or 4-HPR in DLD-1, COLO-205, and SW620 cancer cells. Tamoxifen, 4-HPR, or both, had no effect on the growth of SW-837 (P = .14) cancer cells. Tamoxifen with 4-HPR promoted (P = .02) growth in SW-1463 cells, but not when added separately. Estrogen receptors were not found in any of the cells.

CONCLUSIONS

Under serum-free conditions, Tx, 4-HPR, or both, inhibit the growth of human colon cancer cells but not of rectal cancer cells. Combined treatment with Tx and 4-HPR is more effective than treatment with either of the agents alone in inhibiting of cell growth. The mechanism of inhibition is not clear yet, and further studies are warranted.

Physical localization of microsatellite markers at the ataxia-telangiectasia locus at 11q22-q23

The autosomal recessive disorder ataxia-telangiectasia (A-T) is genetically heterogeneous, with four complementation groups. The genes for the two major groups (ATA and ATC) have been mapped to 11q22-q23. Genetic analysis of the disease has been conducted to date using biallelic polymorphisms. We have physically mapped to this region eight new microsatellite markers that were generated by three laboratories that construct whole-genome linkage maps. These markers should be valuable for refined localization and positional cloning of the A-T genes and for diagnostic purposes. The results demonstrate the value of integrating genetic and physical maps generated by different laboratories.