Accurate Determination of Colorectal Polyp Counts Is Not Mission Impossible for Pathologists and Is Essential for Surveillance Interval Decision-Making: A Review of 1294 Specimens

Introduction/Objective

The US Multi-Society Task Force on colorectal cancer updated recommendations in 2020 for follow-up after colonoscopy. This emphasized differential surveillance intervals based on the number of polyps removed. We determined how often we accurately counted the number of polyps and what submission practices allowed accurate quantification.

Methods/Case Report

We reviewed consecutive colorectal polyp cases from 10/1 to 12/31, 2019, excluding inflammatory polyps in inflammatory bowel disease. Pathology reports were reviewed to determine if the polyp number could be determined from history, gross description, and histologic findings. When numbers did not match or were unclear, endoscopy reports and glass slides were reviewed.

Results (if a Case Study enter NA)

601 cases with 1294 specimens were identified. We accurately determined polyp number in 1235 (95.4%) specimens. 1072 (82.8%) specimens were submitted as single polyp per container (SP), while 222 (17.2%) were submitted with > 1 polyp per container (MP). Polyp number was not quantifiable in 58 (26.1%) MP due to 11 labeled as “multiple polyps” in requisition/endoscopy reports and 47 submitted with polyp number different from number of tissue portions seen grossly and microscopically. In 1 (0.1%) SP, polyp number was unclear because separate portions of tissue contained two different diagnoses. Rate of accurate polyp count is significantly different between SP and MP (p<0.01) by Fisher exact test.

Conclusion

We accurately determined number of polyps in most specimens (95.4%) because our gastroenterologists usually submit SP. In MP, polyp count in 26.1% of specimens was unquantifiable. This could lead to uncertainty in surveillance follow-up intervals. Therefore, we recommend submitting one polyp per container.

Correlation of Cks1 and p27kip1 with tumor biologic aggressiveness and survival in gastrointestinal stromal tumor

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Background: The biologic behavior of gastrointestinal stromal tumors (GIST) based upon morphologic parameters is unpredictable. Cyclin dependent kinase-1 (Cks1) plays an important role in the ubiquitination and proteolysis of p27kip1, a negative regulator of protein kinase Cdk2/cyclin E and Cdk2/cyclin A. This study was to ascertain whether Cks1 overexpression and p27kip1 downregulation were predictive of biologic aggressiveness and overall survival in GIST. Methods: Tissue microarray was built from 61 patients with GIST. Pathology reports as well as clinical follow-up were retrieved. Sections were stained with antibodies to p27kip1 and Cks1. Staining was scored for quantity of tumor cells (%) and intensity (0, 1+ weak staining, 2+ strong staining), and a score was calculated from the product of intensity and %. Tumors were evaluated for correlation of p27kip1 and Cks1 expression level with overall survival time and tumor risk stratification. Tumor risk stratification was classified into very low risk, low risk, intermediate risk, and high risk, and is reflective of intrinsic biologic aggressiveness. Actuarial survival curves were estimated using Kaplan Meier method. Results: The tumors show a high frequency of Cks1 expression (92%; 1+, n=39; 2+, n=17). The % expression ranged from 0–90% (mean 37%). The p27kip1 positive rate is 85% (1+, n=20; 2+, n=32). The % expression ranged from 0–90% (mean 48%). Overall survival ranged from 0.1–10.7 years. By univariate analysis of overall survival using Cox regression model, increased p27kip1 expression (continuous variable) is significantly correlated with overall survival (p=0.04), but Cks1 expression does not (p=0.84). In a univariate analysis of p27kip1 and Cks1 (continuous variables) with risk stratification of the tumor using F-test, higher tumor grade has significantly higher Cks1 expression values (p=0.0045). Conclusions: Our study shows that with univariate analysis high expression of Cks1 expression is significantly associated with increased intrinsic biologic aggressiveness, while high expression of p27kip1 is associated with increased overall survival. The lack of correlation of Cks1 and p27kip1 suggests additional p27kip1 independent mechanisms might play a role in the oncogenesis of GIST.

No significant financial relationships to disclose.

Gene expression in papillary thyroid carcinoma reveals highly consistent profiles

Papillary thyroid carcinoma (PTC) is clinically heterogeneous. Apart from an association with ionizing radiation, the etiology and molecular biology of PTC is poorly understood. We used oligo-based DNA arrays to study the expression profiles of eight matched pairs of normal thyroid and PTC tissues. Additional PTC tumors and other tissues were studied by reverse transcriptase-PCR and immunohistochemistry. The PTCs showed concordant expression of many genes and distinct clustered profiles. Genes with increased expression in PTC included many encoding adhesion and extracellular matrix proteins. Expression was increased in 8/8 tumors for 24 genes and in 7/8 tumors for 22 genes. Among these genes were several previously known to be overexpressed in PTC, such as MET, LGALS3, KRT19, DPP4, MDK, TIMP1, and FN1. The numerous additional genes include CITED1, CHI3L1, ODZ1, N33, SFTPB, and SCEL. Reverse transcriptase-PCR showed high expression of CITED1, CHI3L1, ODZ1, and SCEL in 6/6 additional PTCs. Immunohistochemical analysis detected CITED1 and SFTPB in 49/52 and 39/52 PTCs, respectively, but not in follicular thyroid carcinoma and normal thyroid tissue. Genes underexpressed in PTC included tumor suppressors, thyroid function-related proteins, and fatty acid binding proteins. Expression was decreased in 7/8 tumors for eight genes and decreased in 6/8 tumors for 19 genes. We conclude that, despite its clinical heterogeneity, PTC is characterized by consistent and specific molecular changes. These findings reveal clues to the molecular pathways involved in PTC and may provide biomarkers for clinical use.

Eosinophilic pancreatitis: a rare entity that can mimic a pancreatic neoplasm

Eosinophilic pancreatitis is a rare disorder that is frequently diagnosed only after pancreatic resection for suspected pancreatic tumor. It typically occurs in the setting of either eosinophilic gastroenteritis or the hypereosinophilic syndrome. Isolated eosinophilic infiltration of the pancreas is less common. We describe a case of a 36-year-old man who presented with the clinical symptoms of acute pancreatitis. Radiologic evaluation revealed an obstructive pancreatic lesion suspicious for carcinoma. Pathologic examination of the resection specimen revealed a dense infiltrate of eosinophils in the pancreas. Although an uncommon condition, eosinophilic pancreatitis is a syndrome lacking well-defined causes that can be associated with eosinophilic gastroenteritis, a treatable condition, or the potentially fatal hypereosinophilic syndrome. While the radiographic features of this condition can vary widely, eosinophilic infiltration of the pancreas with or without involvement of the gastrointestinal tract is the pathologic feature common to all of the previously reported cases.

Fine mapping of the friend retrovirus resistance gene, Rfv3, on mouse chromosome 15

Rfv3 is a host resistance gene that operates through an unknown mechanism to control the development of the virus-neutralizing antibody response required for recovery from infection with Friend retrovirus. The Rfv3 gene was previously mapped to an approximately 20-centimorgan (cM) region of chromosome 15. More refined mapping was not possible, due to a lack of microsatellite markers and leakiness in the Rfv3 phenotype, which prevented definitive phenotyping of individual recombinant mice. In the present study, we overcame these difficulties by taking advantage of seven new microsatellite markers in the Rfv3 region and by using progeny tests to accurately determine the Rfv3 phenotype of recombinant mice. Detailed linkage analysis of relevant crossovers narrowed the location of Rfv3 to a 0.83-cM region. Mapping of closely linked genes in an interspecific backcross panel allowed us to exclude two previous candidate genes, Ly6 and Wnt7b. These studies also showed for the first time that the Hsf1 gene maps to the Rfv3-linked cluster of genes including Il2rb, Il3rb, and Pdgfb. This localization of Rfv3 to a region of less than 1 cM now makes it feasible to attempt the cloning of Rfv3 by physical methods.

Induction of molecular remission by donor peripheral blood leukocyte therapy in patients relapsing with extramedullary blastic phase chronic myeloid leukemia after allogeneic bone marrow transplantation

Two patients with chronic myeloid leukemia (CML) who relapsed in blastic transformation after allogeneic bone marrow transplantation (BMT) were treated with infusions of leukapheresed peripheral blood mononuclear cells from their original donor. At relapse, their disease was characterized by symptomatic extramedullary deposits of leukemia with minimal (PCR positive, cytologically negative) involvement of bone marrow. Treatment with donor cell infusions was associated with clinical remission, return of full donor chimerism and loss of the BCR-ABL transcript detectable in bone marrow before donor leukocyte infusion (molecular remission). Donor leukocyte infusions should be considered for therapy of relapsed blastic phase CML after allogeneic BMT, especially when the relapse is primarily extramedullary and responsive to local and systemic cytoreductive therapy. However, severe GVHD and CNS relapse remain obstacles to achieving a successful long-term outcome.

Behavioral phenotypes of inbred mouse strains: implications and recommendations for molecular studies

Choosing the best genetic strains of mice for developing a new knockout or transgenic mouse requires extensive knowledge of the endogenous traits of inbred strains. Background genes from the parental strains may interact with the mutated gene, in a manner which could severely compromise the interpretation of the mutant phenotype. The present overview summarizes the literature on a wide variety of behavioral traits for the 129, C57BL/6, DBA/2, and many other inbred strains of mice. Strain distributions are described for open field activity, learning and memory tasks, aggression, sexual and parental behaviors, acoustic startle and prepulse inhibition, and the behavioral actions of ethanol, nicotine, cocaine, opiates, antipsychotics, and anxiolytics. Using the referenced information, molecular geneticists can choose optimal parental strains of mice, and perhaps develop new embryonic stem cell progenitors, for new knockouts and transgenics to investigate gene function, and to serve as animal models in the development of novel therapeutics for human genetic diseases.

Detection of chimerism and early engraftment after allogeneic peripheral blood stem cell or bone marrow transplantation by short tandem repeats

Chimerism can be monitored after HLA-matched allogeneic bone marrow transplantation (BMT) or allogeneic peripheral blood stem cell transplantation (PBSCT) by detecting polymorphisms in short tandem repeats (STR). The purpose of our study was to document early complete chimerism in BMT and PBSCT recipients using STR, and to determine whether the initial WBC recovery correlated with the days required to attain complete chimerism. A total of 5 patients (2 PBSCT and 3 BMT) were followed by STR after transplantation. Peripheral blood obtained prior to transplantation was used to determine the 2 most informative STR probes for each donor/recipient pair. STR were amplified by polymerase chain reaction (PCR) with 8 commercial probes, and PCR products were visualized with silver staining. Peripheral blood was evaluated daily post-transplantation for WBC counts and to identify the presence of mixed or full chimerism by STR. The sensitivity of the STR technique varied from 0.05 to 1%, depending on the probe. Full chimerism was documented between day 9 and 14 in PBSCT recipients and on day 14 and 16 in BMT recipients. The initial rise in WBC occurred within 3 days of the onset of full chimerism, indicating that full chimerism is a more sensitive indicator of early engraftment. Periodic recipient monitoring using STR after complete chimerism identifies those patients who revert to mixed chimeras. The STR method may be useful in future studies to determine the significance of early engraftment and the clinical implications of sustained complete chimerism or mixed chimerism.

Resection-induced colonic adaptation is augmented by IGF-I and associated with upregulation of colonic IGF-I mRNA

The effects of exogenous insulin-like growth factor-I (IGF-I) on colonic adaptation were examined in male Sprague-Dawley rats (n = 60, 225-275 mg) after either a 60% small bowel and cecal resection (RX) or mid-small bowel transection with reanastomosis (TX). Animals received a 7-day treatment with either IGF-I (2.4 mg.kg-1.day-1) or vehicle (V; 0.1 mol/l acetic acid). Body weight decreased significantly after resection (-25.6 +/- 4.0 g; P < 0.05 vs. TX/V). IGF-I treatment significantly reduced weight loss after resection (-12.4 +/- 3.8 g; P < 0.01 vs. RX/V) and induced significant weight gain after transection (15.6 +/- 4.0 g; P < 0.05 vs. TX/V). Plasma IGF-I decreased with resection (526 +/- 41 TX/V vs. 344 +/- 17 ng/ml RX/V; P < 0.01). IGF-I treatment significantly increased plasma IGF-I levels (805 +/- 100 ng/ml TX/IGF, 677 +/- 56 ng/ml RX/IGF). After resection, IGF-I treatment significantly increased colonic mucosal weight, DNA, protein content, and crypt depth when compared with resection alone (P < 0.05). Colonic water absorption, measured by an in vivo [3H]polyethylene glycol assay, was significantly increased by IGF-I treatment in resected animals (399 +/- 23 RX/IGF vs. 306 +/- 32 microliter.cm-1.h-1 RX/V; P < 0.05). Resection resulted in increased steady-state colonic IGF-I mRNA (182% of TX/V; P < 0.01) without significantly affecting IGF-I receptor mRNA expression. Regulation of IGF binding protein (BP)-3 and -4 was discoordinate, with IGFBP-3 mRNA tending to decrease with resection (67% of TX/V; P is not significant) and IGFBP-4 increasing significantly (191% of TX/V; P < 0.05). An important role for IGF-I in colonic adaptation after massive intestinal resection is indicated by 1) significantly enhanced colonic mucosal growth and water absorption with IGF-I treatment and 2) postresection upregulation of colonic IGF-I mRNA and alteration of IGFBP-3 and IGFBP-4 mRNA expression.

Fiber: effect on bacterial translocation and intestinal mucin content

Total parenteral nutrition (TPN) and elemental diet (ED) produce intestinal atrophy and increase bacterial translocation (BT) to mesenteric lymph nodes. The increased rate of BT may be due to alterations in mucosal structure, enzyme activity, or mucin content. Fiber improves intestinal structure and function in rats and may reduce the rate of BT. This study determined whether the addition of fiber to TPN or ED would maintain intestinal integrity and decrease BT to the mesenteric lymph nodes. Fifty-six adult male Sprague-Dawley rats underwent placement of jugular catheters and were assigned to one of five dietary groups: TPN, TPN+oral oat fiber (TPNF) 2 g/day, ED, ED+oral oat fiber (EDF) 2 g/day, or AIN-76 (control); they were pair-fed for 7 days. On day 8 the mesenteric lymph nodes were removed for bacterial cultures; and jejunal mucosal weight, DNA, protein, alkaline phosphatase, maltase, and jejunal mucin content were measured. Enteral nutrition significantly decreased BT when compared to parenteral feeding, and fiber significantly decreased BT when administered to rats receiving TPN or ED. Improvements in intestinal mucosal structure were not consistently associated with decreased rates of BT. Additionally, BT occurred independently of jejunal mucin concentration. Mechanisms other than maintenance of mucosal structure or mucin content are important in the mediation of fiber-induced decreased BT in rats receiving TPN or ED.

Butyrate increases colonocyte protein synthesis in ulcerative colitis

Butyrate promotes epithelial cell healing and improves symptoms when administered rectally in patients with distal ulcerative colitis (UC). It was hypothesized that butyrate may enhance healing in patients with UC by stimulating colonocyte proliferation and/or protein production. Mucosa from the descending colon was obtained from patients with UC (n = 5), Crohn's disease (n = 8), diverticulitis (n = 6), and cancer (normal tissue 10 cm from tumor; n = 10). Epithelial cells were isolated using dispase/collagenase and differential sedimentation and incubated for 4 hr at 37 degrees C with either Na butyrate (10 mM) or NaCl (10 mM). Protein synthesis was assessed by [14C]leucine incorporation and proliferation was determined with [3H]thymidine. Mean viability and purity were >88%. Spontaneous proliferation was significantly increased in UC when compared to diverticulitis and normal controls. Butyrate significantly increased protein synthesis in UC epithelial cells when compared to saline control. The therapeutic effects of butyrate in patients with UC may be due to its use by epithelial cells as a metabolic fuel to increase protein production and promote healing.

A comparison between operative and nonoperative management of blunt injuries to the liver and spleen in adult and pediatric patients

Nonoperative management of blunt trauma involving the liver and spleen has been accepted in stable pediatric patients but has been controversial in adult patients. The purpose of this study was to compare nonoperative management of blunt liver and spleen injuries in adult patients with a similar group of adult patients treated operatively and with a group of pediatric patients treated nonoperatively. A 5-year retrospective study was carried out on all hemodynamically stable patients who came to our institution with blunt abdominal trauma. There were 20 adults treated operatively (group I), 25 adults treated nonoperatively (group II), and 34 pediatric patients treated nonoperatively (group III). The mean acute physiology and chronic health evaluation score for group I was 5.1; group II, 3.1; and group III, 7.9. Delayed splenectomy was required in four adult patients in group I and in one patient in group III. There were no deaths. The mean total blood requirement was 6.0 units for group I, 2.8 units for group II, and 1.7 units for group III. The average hospital stay was 19.1 days for group I, 12.6 days for group II, and 9.2 days for group III. These data suggest that the outcome of adult patients whose blunt liver and spleen injuries are managed nonoperatively is comparable with that of pediatric patients treated nonoperatively and is as good as that of adults undergoing early laparotomy.

Mitotic recombination is responsible for the loss of heterozygosity in cultured murine cell lines

Heterozygous mammalian cell lines normally express both parental alleles at most autosomal loci. However, mutants can be isolated that fail to express one of the alleles. Using a murine pre-B cell line that is heterozygous for several loci on chromosome 12, including one encoding the cell surface antigen Ly-18, we found that one of the two Ly-18 antigenic forms was lost at a rate of 1.5 x 10(-5) per cell per generation. Molecular analysis revealed that a genetic marker distal to Ly-18 became homozygous. Analysis of the genotype of the mutants at the rDNA cluster, located close to the centromere, strongly suggests that the mutants arose by mitotic recombination within this multicopy locus.

Mitotic recombination between homologous chromosomes generates H-2 somatic cell variants in vitro

A spontaneously arising variant clone that does not express the H-2Dd and H-2Ld molecules was isolated by immunoselection from an (H-2b X H-2d)F1 cell line. This variant clone expresses H-2Kb, H-2Db, and H-2Kd molecules. Southern blot analysis demonstrated that the variant was heterozygous at the H-2K, I, and S loci but had lost the H-2Dd and H-2Ld genes. Karyotype analysis showed that neither of the chromosome 17s in the variant had undergone detectable deletions. Quantitative Southern blot analysis demonstrated that the variant had two copies of the H-2Db gene, whereas the parental cell line had one copy of H-2Db. The loss of the H-2Ld and H-2Dd genes, accompanied by the attainment of homozygosity at H-2Db, is consistent with a recombination between the two chromosome 17 homologues. We conclude that although mitotic recombination between homologues has been difficult to demonstrate, it may not be infrequent and may account for the development of mutant genotypes in somatic cells in vitro. Such a mechanism occurring in vivo could result in the emergence of cells that are homozygous for deleterious alleles even though the individual may be constitutionally heterozygous.

Spontaneous deletion at the B2m locus: evidence for site-specific genetic rearrangement

We have isolated 20 independent spontaneous mutants in the B2mb allele from a B2ma/b heterozygous murine cell line by immunoselection in vitro with a monoclonal antibody directed against the product of the B2mb allele. One class of mutants has undergone a deletion in the 5' end of the B2mb gene. The deletions appear to be identical in all of the independent clones, and extend an unknown distance upstream of the B2m gene from a region in the first intron. Southern blot analysis with the use of oligonucleotides to the wild type gene sequence mapped the breakpoint to within 39 base pairs. The high frequency of independent spontaneous mutants showing indistinguishable deletions suggests that the first intron of the B2m gene contains sequences that are highly susceptible to site-specific recombinations.

Spontaneous deletion at the B2m locus: evidence for site-specific genetic rearrangement

We have isolated 20 independent spontaneous mutants in the B2mb allele from a B2ma/b heterozygous murine cell line by immunoselection in vitro with a monoclonal antibody directed against the product of the B2mb allele. One class of mutants has undergone a deletion in the 5' end of the B2mb gene. The deletions appear to be identical in all of the independent clones, and extend an unknown distance upstream of the B2m gene from a region in the first intron. Southern blot analysis with the use of oligonucleotides to the wild type gene sequence mapped the breakpoint to within 39 base pairs. The high frequency of independent spontaneous mutants showing indistinguishable deletions suggests that the first intron of the B2m gene contains sequences that are highly susceptible to site-specific recombinations.

Retroviral insertional mutagenesis of a target allele in a heterozygous murine cell line

A clonal murine cell line that is heterozygous at the beta 2-microglobulin locus (B2m) was obtained by Abelson murine leukemia virus (Ab-MuLV) transformation of liver cells from (C57BL/6 X BALB/c) F1 fetuses. To obtain proviral insertional mutants, we superinfected a subclone of these cells, which does not express the env surface protein of the Moloney leukemia virus (Mo-MuLV, the helper virus that was used to transmit the defective Ab-MuLV genome during transformation), with Mo-MuLV. Mutant clones that fail to express the C57BL/6 allele of B2m (B2mb) were then immunoselected by using a monoclonal antibody that specifically recognizes the B2mb gene product and not that of the B2ma allele. Of 22 independent clones obtained, one contains a proviral insertion that is near or in the first exon of the B2mb gene. Surprisingly, the insertion is of the Ab-MuLV genome and not of replication-competent Mo-MuLV. This indicates that superinfection with Mo-MuLV "rescued" the defective Ab-MuLV genome, which then inserted into the B2mb gene. We conclude that when an allele-specific selection procedure exists, proviral insertion is a potential method for obtaining mutations in heterozygous mammalian cells. This approach may thereby provide a method for molecular cloning of such selectable genes, using a retroviral hybridization probe.