Heat and moisture exchanger cassettes: Results of a quality/safety initiative to reduce postoperative mucus plugging after total laryngectomy

BACKGROUND

Tracheal dryness is a concern after total laryngectomy due to the potential for mucus plugs (MP). This study compared heat and moisture exchanger (HME) cassettes to external tracheal humidification (ETH) surrounding MP events.

METHODS

A retrospective comparative cohort study comparing outcomes before/after implementation of a patient safety initiative utilizing HME during post laryngectomy hospitalization. The number of MP events were compared with a pre-implementation control group using ETH. Patient characteristics were analyzed for correlation with MP.

RESULTS

The rate of MP was significantly lower in the HME group than ETH (0.13 and 0.38 per 10 inpatient days, respectively, P = .02). The proportion of patients with one or more MP events was also significantly reduced in the HME group (50% ETH and 11% HME, P = .01). Method of humidification was the only significant variable associated with MP on logistic regression modeling (P = .008).

CONCLUSIONS

HMEs were superior to ETH for prevention of MP.

Dysphagia Screening for Pneumonia Prevention in a Cancer Hospital: Results of a Quality/Safety Initiative

OBJECTIVE

Hospital-acquired aspiration pneumonia remains a rare but potentially devastating problem. The best means by which to prevent aspiration in a cancer hospital population has not been evaluated. The aim of this study was to evaluate the impact of dysphagia screening on aspiration pneumonia rates in an acute care oncology hospital.

METHODS

A prospective single-institution quality improvement dysphagia screening protocol at a comprehensive cancer center. Effect of dysphagia screening implemented in 2016 on hospital-acquired aspiration pneumonia rates coded "aspiration pneumonitis due to food/vomitus" was compared with rates from 2014 to 2015 prior to implementation. Screening compliance, screening outcomes, patient demographics, and medical data were reviewed as part of a post hoc analysis.

RESULTS

Of 12,392 admissions in 2014 to 2016, 97 patients developed aspiration pneumonia during their hospitalization. No significant change in aspiration pneumonia rate was seen during the dysphagia screening year when compared to prior years (baseline, 7.36; screening year, 8.78 per 1000 discharges; P = .33). Sixty-eight of the cases (66%) were associated with emesis/gastrointestinal obstruction or perioperative aspiration and only 15 (15%) with oropharyngeal dysphagia. Multivariate analysis found that patients admitted to gastrointestinal surgery had an aspiration risk equivalent to patients admitted to head and neck, thoracic, and pulmonary services (odds ratio, 0.65; P = .2).

DISCUSSION

Nursing-initiated dysphagia screening did not decrease aspiration pneumonia rates. The causes of aspiration-associated pneumonia were heterogeneous. Aspiration of intestinal contents is a more common source of hospital-acquired pneumonia than oropharyngeal dysphagia.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Low-Dose Anti-Thymocyte Globulin (ATG) Preserves β-Cell Function and Improves HbA1c in New-Onset Type 1 Diabetes

OBJECTIVE

A pilot study suggested that combination therapy with low-dose anti-thymocyte globulin (ATG) and pegylated granulocyte colony-stimulating factor (GCSF) preserves C-peptide in established type 1 diabetes (T1D) (duration 4 months to 2 years). We hypothesized that 1) low-dose ATG/GCSF or 2) low-dose ATG alone would slow the decline of β-cell function in patients with new-onset T1D (duration <100 days).

RESEARCH DESIGN AND METHODS

A three-arm, randomized, double-masked, placebo-controlled trial was performed by the Type 1 Diabetes TrialNet Study Group in 89 subjects: 29 subjects randomized to ATG (2.5 mg/kg intravenously) followed by pegylated GCSF (6 mg subcutaneously every 2 weeks for 6 doses), 29 to ATG alone (2.5 mg/kg), and 31 to placebo. The primary end point was mean area under the curve (AUC) C-peptide during a 2-h mixed-meal tolerance test 1 year after initiation of therapy. Significance was defined as one-sided P value < 0.025.

RESULTS

The 1-year mean AUC C-peptide was significantly higher in subjects treated with ATG (0.646 nmol/L) versus placebo (0.406 nmol/L) (P = 0.0003) but not in those treated with ATG/GCSF (0.528 nmol/L) versus placebo (P = 0.031). HbA_1c was significantly reduced at 1 year in subjects treated with ATG and ATG/GCSF, P = 0.002 and 0.011, respectively.

CONCLUSIONS

Low-dose ATG slowed decline of C-peptide and reduced HbA_1c in new-onset T1D. Addition of GCSF did not enhance C-peptide preservation afforded by low-dose ATG. Future studies should be considered to determine whether low-dose ATG alone or in combination with other agents may prevent or delay the onset of the disease.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Phase II evaluation of cetuximab (C225) combined with induction paclitaxel and carboplatin followed by C225, paclitaxel, carboplatin, and radiation for stage III/IV operable squamous cancer of the head and neck (ECOG, E2303)

6015

Introduction: Neoadjuvant C225 with induction chemotherapy and chemo-radiation was studied in stage III/IV head and neck squamous cancer with primary and secondary objectives of 1year event- free survival, pathologic complete response rate at the primary site (PS) (determined by mandatory biopsy week 8) and toxicity. Protocol Design: Operable patients (pts) staged by triple endoscopy, CT/MRI, had gastrostomy, signed IRB approved consent and received induction chemotherapy with weekly C225 250 mg/m2, P 90 mg/m2, C (AUC=2). Restaging PS biopsy was done at week 8, if there was a clinical response. Pts with positive biopsy (or persistent tumor) at PS had restaging biopsy at week 14 after chemo radiation (C225 250 mg/m2, P 30 mg/m2, C(AUC=1) and 50 Gy). If PS Bx was negative patients had completion RT (68–72 Gy, plus continued C225, P,C). If PS Bx was positive at 14 weeks salvage surgery was required. Results: 74 patients were enrolled (67 are evaluable). T and N stage were T1/2 (11%/27%), T ¾ (47%/14%); N O/N1 (11%/23 %), N 2/3 (50%/16%). Site: tonsil 30%, oral cavity/tongue 24%, Post pharynx (BOT) 42%, Larynx 34%; performance status 0/1 (61% / 39%). PS re biopsy was done at week 8 in 40 patients; no residual tumor was detected in 26 (65%). Restaging biopsy after induction and chemo radiation was done at week 14 in 28 pts (14 with persistent tumor and 14 with previous positive biopsy) and was negative in all 28 patients. All 54 patients with negative PS biopsy had completion RT. Data on disease status are incomplete. Post treatment toxicity (Gr 3/4) included acneiform rash (12%), leukopenia/neutropenia 32%/24%, dysphagia (29%), and stomatitis (82%). One grade 5 AE occurred (death from encephalopathy). Conclusion: Neoadjuvant induction C225, plus chemotherapy followed by C225 plus chemo-radiation elicited a complete pathologic response at the primary site, by restaging biopsy (65%) with induction alone, and 100% among sampled patients after chemo RT 50Gy. These preliminary results suggest a high pathologic complete response rate to induction chemotherapy plus cetuximab followed by chemo radiation plus cetuximab. Progression and survival data are not yet mature.

No significant financial relationships to disclose.

Prognostic significance of human papillomavirus (HPV) tumor status for patients with head and neck squamous cell carcinoma (HNSCC) in a prospective, multi-center phase II clinical trial

6000

Background: Retrospective, single-institution studies suggest that patients with HPV- positive (HPV+) HNSCC may have a better prognosis than patients with HPV-negative (HPV-) tumors. Methods: The effect of tumor HPV status on treatment response and survival outcomes was prospectively evaluated in a multi-center, phase II clinical trial conducted by the Eastern Cooperative Oncology Group. Patients with newly diagnosed, resectable, stage III or IV HNSCC of the oropharynx or larynx were uniformly treated with two cycles of induction chemotherapy (IC; paclitaxel 175 mg/m2 and carboplatin AUC 6) followed by chemoradiation (CRT; weekly paclitaxel 30 mg/m2 administered concurrently with standard fractionation external beam radiation therapy, total dose of 70 Gy in 35 fractions over 7 weeks). Tumor HPV status was determined by in situ hybridization on formalin-fixed, paraffin-embedded tumors. The independent effect of tumor HPV status on survival was evaluated by Cox-proportional hazards models. Results: Genomic DNA of oncogenic HPV type 16, 33, or 35 was specifically located within tumor cell nuclei of 40% (95%CI 29.7- 50.1) of evaluable cases. Factors associated with HPV+ tumor in univariate analysis included Caucasian race (p=0.02), improved ECOG performance status (p=0.01), an oropharyngeal primary (p<0.001), early tumor stage (p=0.02), and basaloid histology (P<0.001). Response rates assessed after IC (81.6% vs. 55.2%, p=0.01) and CRT (84.2% vs. 56.9%, p=0.07) were higher in patients with HPV+ than HPV- tumors. After a median follow-up time of 39.1 months, patients with HPV+ tumors had a risk of progression that was 72% lower (HR=0.28, 95% CI: 0.07–1.0) and a risk of death that was 79% lower (HR=0.21, 95% CI: 0.06–0.74) than patients with HPV- tumors, after adjustment. Conclusion: The improved prognosis of HPV+ HNSCC has been confirmed in a prospective clinical trial and may be explained in part by enhanced sensitivity to chemotherapy and radiation.

No significant financial relationships to disclose.

Long-term results of Intergroup RTOG 91–11: A phase III trial to preserve the larynx—Induction cisplatin/5-FU and radiation therapy versus concurrent cisplatin and radiation therapy versus radiation therapy

5517

Background: The 2-year results of Intergroup RTOG 91–11 were published in 2003 (NEJM 349:2091–8,2003). We now present the 5-year results (after median follow-up for surviving patients of 6.9 years) of 515 eligible pts with resectable stage III or IV (excluding T1 and high volume T4), cancer of the glottic or supraglottic larynx. Methods: Patients were randomized to induction cisplatin/5-FU (CF) with responders then receiving RT (I+RT) (n = 173); or concurrent cisplatin (100 mg/m2 q 21 days × 3) and RT (CRT) (n = 171); or RT alone (R) (n = 171). Laryngectomy was performed for < partial response to induction CF, for persistent/recurrent disease or for laryngeal dysfunction. Results: At 5 years, laryngectomy-free survival (LFS) was significantly better with either I+RT (44.6%, p = 0.011) or CRT (46.6%, p = 0.011) compared to R (33.9%). There was no difference in LFS between I+RT and CRT (p = 0.98). Laryngeal preservation (LP) was significantly better with CRT (83.6%) compared to I+RT (70.5%, p = 0.0029) or R (65.7%, p = 0.00017). Local-regional control (LRC) was significantly better with CRT (68.8%) compared to I+RT (54.9%, p = 0.0018) or R (51%, p = 0.0005). I+RT compared to R for LP and LRC showed no significant difference (p = 0.37 and 0.62, respectively). The distant metastatic rate was low (I+RT 14.3%, CRT 13.2%, R 22.3%) with a trend (p ∼0.06) for benefit from chemotherapy. Disease-free survival (DFS) was significantly better with either I+RT (38.6%, p = 0.016) or CRT (39%, p = 0.0058) compared to R (27.3%). Overall survival rates were similar for the first 5 years (I+RT 59.2%, CRT 54.6%, R 53.5%); thereafter I+RT had a non-significant lower death rate. Compared to CRT, significantly more pts in the R group died of their cancer (34% vs 58.3%, p = 0.0007); the rate for I+RT was 43.8%. Conclusion: These 5-year results differ from the 2-year analysis by a significant improvement in LFS now seen for both I+RT and CRT treatments compared to R. For the endpoints of LP and LRC, CRT is still the superior treatment with no advantage seen to the addition of induction CF to R. There is no significant difference in overall survival.

[Table: see text]

Effects of gamma-IFN and NGF on subpopulations in a human neuroblastoma cell line: flow cytometric and morphological analysis

Neuroblastomas are neural crest-derived tumors that contain neuronal, melanocyte, and Schwann cell precursors. We examined the effects of treatment with gamma-interferon (gamma-IFN) and nerve growth factor (NGF), alone, and in combination, on these progenitor subpopulations in the human neuroblastoma cell line, SH-SY5Y. Using fluorescence-activated flow cytometry (FACS), changes in expression of three differentiation-specific or -associated marker proteins, the 200 kD neurofilament protein, the myelin basic protein, and the S-100 protein, were analyzed. Growth rates and morphological changes associated with each treatment over the 2-wk incubation period were noted. The greatest effects were observed with combined IFN + NGF treatment. These were significant increases in expression of all three proteins, distinctive morphological signs of differentiation, and extensive inhibition of proliferation compared to control cultures. Treatment with NGF alone resulted in increased neurofilament protein expression and in the length and number of neurite extensions, but there was no effect on the growth rate. IFN induced striking morphological changes, significant inhibition of growth, and changes in protein expression that correlated with neuronal to non-neuronal subpopulation shifts due to the death of differentiated cells. When treatment was discontinued after 15 d, the morphological changes induced by NGF were reversed within 2-3 d, while those induced by IFN +/- NGF were present up to 4 wk post-treatment. Small, neuroblastic colonies were observed throughout the treatment period and within 4-6 wk after the cessation of treatment this cell-type fully reconstituted the cultures suggesting the presence of a stem cell. Our results indicate that treatment with gamma-IFN +/- NGF can regulate growth and induce, either stem cells or progenitor neuronal, Schwann and melanocyte subpopulations in the SH-SY5Y cell line to irreversibly differentiate.

Traumatic medial displacement of Rotalok uncemented acetabular component. A case report

The failure of uncemented acetabular components has been described in association with component wear, disassembly, and proximal migration. The authors report a case of medial displacement following minor trauma some 18 months after surgery. The component involved differs in design from both press-fit, porous-coated or screw-in, fully threaded acetabular cups. The authors suggest that additional screws should be inserted to enhance long-term stability.

Consistent selection of mutations in the 5'-untranslated region of oral poliovirus vaccine upon passaging in vitro

We have previously found that upon passaging type 3 oral poliovirus vaccine (OPV) in cell cultures the proportion of revertants at nucleotide 472 rapidly increases [Chumakov et al.: Proceedings of the National Academy of Sciences of the United States of America 88:199-203 1991]. Systematic study on the accumulation of these revertants showed that it was dependent on the multiplicity of infection and the temperature at which virus was grown. Revertants at position 472 of type 3 OPV accumulated faster in vaccines derived from Sabin Original (SO) substrain than from RNA-plaque purified (RSO) substrain. The rate of accumulation of 472-C revertants differed among cell lines and was higher in overgrown cell cultures suggesting that host factors are involved in the selection of mutants. We also found that accumulation of mutants occurred in vitro at position 480 in type 1 and position 481 in type 2 OPV, making the selection for revertants in domain F of the 5'-noncoding region a general phenomenon for all three Sabin strains. Assessment of the abundance of these mutants may be used for evaluation of the quality of OPV lots.

Propagation and properties of Kaposi's sarcoma-derived cell lines obtained from patients with AIDS: similarity of cultured cells to smooth muscle cells

Cells derived from Kaposi's sarcoma (KS) were propagated in vitro using conditions which resulted in elimination of contaminating fibroblasts and the emergence of homogeneous cell populations which morphologically resembled smooth muscle cells and had neoplastic characteristics. In long-term culture, they differentiated into large ribbon-like cells with longitudinal fibrillarity of their cytoplasm. These fibrils stained red by Masson trichrome staining, and were reactive with antibodies to desmin. Dense bodies typical of myoblasts were observed in some cells by electron microscopy. The cells did not form capillary structures like endothelial cells, they lacked Weible-Palade bodies, and did not express the blood-clotting Factor VIII-related antigen or receptors for the lectin Ulex europaeus agglutinin I. They did express four other antigens, however, in common with endothelial cells. The cells did not form tumors in athymic nude mice; however, they formed colonies in soft agar, manifested tumor-like growth on muscle organ cultures, and were invasive in an artificial basement membrane invasion assay. The results indicate that a component of KS is closely related to leiomyoblasts and and has neoplastic properties.

Dynamics of differentiation in human epidermoid squamous carcinoma cells (A431) with continuous, long-term gamma-IFN treatment

We investigated the long-term effects of continuous gamma interferon (gamma-IFN) treatment on A431, a human squamous carcinoma cell line. Cells were grown in an in vitro culture system, which over time produces cohesive cell masses ("tumoroids") exhibiting three-dimensional, histotypically differentiated structures, e.g., keratin "pearls", intercellular bridges (desmosomes), elongated flattened cells (squames) and stratification. The effects of gamma-IFN on cell growth, morphology and stage of differentiation were assessed at different treatment times by light and electron microscopy and by immunohistochemical staining using antibodies to keratins 1 and 14 and to filaggrin, markers of specific stages of keratinocyte differentiation. Our results show that A431 cells have the capacity for spontaneous differentiation, that this capacity is significantly enhanced and accelerated by gamma-IFN treatment leading to terminal differentiation and extensive cell death by 2 wk. Despite continuous exposure to IFN, a small number of viable, undifferentiated cells remain. Their proliferation, evident by 3 wk, reconstitutes the tumoroid which once again contains the full range of differentiating cell types.

Pharmacokinetic studies of mouse monoclonal antibodies to a rat colon carcinoma: I. Comparison of biodistribution in normal rats, syngeneic tumor-bearing rats, or tumor-bearing nude mice

The pharmacokinetics of two iodine-131-(131I) labeled murine anti-rat colon carcinoma monoclonal antibodies (D3 and E4) were compared in normal Sprague Dawley rats, syngeneic BDIX rats, or nude mice bearing that tumor. Results of antibody uptake after i.v. administration were analyzed in terms of accumulation and localization indices for normal tissues and tumor. Statistically significant differences between rat and mouse tissue biodistribution were found. D3, which reacts in vitro with the tumor and several normal rat tissues, cleared quickly from the blood of rats and was specifically targeted to several normal tissues, notably the lung. Virtually no targeting to the tumor was observed. Nude mice, however, showed a slower blood clearance and specific antibody targeting only in the tumor. Similar results were seen after injection of another antibody, E4, which is tumor-specific in vitro. Data suggest that studies on the xenogeneic nude mouse model may not necessarily be relevant to the choice of monoclonal antibodies for clinical diagnostic imaging or therapy.

Monoclonal antibodies to a rat colon carcinoma: model for monoclonal antibody therapy of solid tumors

Tumor progression, lung metastasis, and death occur in tumor-bearing BD IX syngeneic rats in a fashion similar to the course of patients with metastatic colon cancer. In an effort to establish a relevant model for monoclonal antibody (MoAb) therapy of tumors, we generated murine MoAb against DHD/TR, a dimethylhydrazine-induced rat colon carcinoma which has been adapted to cell culture. Murine MoAb 17B10 E4 (E4) reacts with the TR tumor and shows weak immunoperoxidase reactivity with normal rat tissues. Murine MoAb 5F7 D3 (D3) reacts with the tumor and a variety of normal rat epithelia. Both are IgG2a and mediate cytotoxicity by rat peripheral blood mononuclear cells. 18D5 F6 (F6) also reacts with the tumor and normal tissues but is an IgG2b and does not mediate cytotoxicity in the presence of rat effector cells. Iodinated E4 and D3 antibodies retained their immunoreactivity. E4 revealed 9.8 x 10(5) antigenic sites per TR cell, with an affinity constant of 9.35 x 10(7) M-1, while D3 demonstrated 2.5 x 10(6) antigenic sites and an affinity constant of 4.2 x 10(7) M-1. Immunoblotting showed that the antigens recognized by D3 and E4 are glycoproteins with molecular weights of 27,000 and 66,000, respectively. F6 failed to react with its antigen present in the blot. This rat colon carcinoma and the monoclonal antibodies described here may provide experimental data useful for implementing monoclonal antibodies in cancer therapy.

Interferon-gamma induces altered oncogene expression and terminal differentiation in A431 cells

In tumor cell lines in which oncogene expression is abnormal, modulation of the expression of the oncogene (myc, src, or ras) by interferons (IFNs) has been observed concurrently with cell growth inhibition or phenotypic reversion. Oncogene expression has also been reported to vary during the differentiation of several neoplastic cell lines. Treatment of monolayer cultures of A431, a human epidermoid carcinoma cell line, with IFN-gamma resulted in rapid morphological alterations and cell death not seen with either IFN-alpha or IFN-beta. These changes were accompanied by elevated expression of mRNA's for p21 (the c-ras gene product) and the epidermal growth factor receptor as well as increases in the biosynthetic rate of their respective proteins. These effects likewise appeared to be specific for IFN-gamma. Growth inhibition by IFN-gamma was also observed when A431 cells were grown in a three dimensional in vitro culture system. Immunohistochemical staining of these "tumoroids" with a differentiation specific, anti-keratin antibody indicated that IFN-gamma enhanced expression of this keratin. This observation suggests that the killing by IFN-gamma of A431 cells may result from an acceleration of terminal differentiation.

The use of flow cytometry and cell sorting in a human colon carcinoma model

We investigated the growth characteristics of a human colon carcinoma cell line, WiDr, grown in culture flasks and on chick embryonic skin (CES). WiDr cells labeled in vitro with bromodeoxyuridine (BrdU) and analyzed by combined propidium iodide/Hoechst 33258 fluorescence showed evidence of more BrdU incorporation in early S phase as compared to late S phase. When inoculated on the CES, WiDr cells multiplied and invaded the underlying skin. Morphologic examination showed that with extended culture WiDr cells on the CES undergo progressive structural organization with the development of acini and basal lamina, structures similar to those in in vivo tumors. WiDr cells were labeled with monoclonal antibody to carcinoembryonic antigen (CEA) and the brightest 2% of the population was sorted. When subsequently grown on the CES, the sorted cells formed significantly more acinar structures at 3 and 6 days of culture than an unsorted population grown for a comparable time.

Influence of spatial configuration of carcinoma cell populations on the expression of a tumor-associated glycoprotein

Monoclonal antibody B72.3 was generated using a membrane-enriched fraction of cells from a mammary carcinoma metastasis and has been shown previously to have a high degree of selective reactivity for human breast and colon carcinoma versus normal adult tissues. The reactive antigen has been shown to be a high-molecular-weight glycoprotein complex of approximately 220,000 to 400,000 and is termed tumor-associated glycoprotein 72 (TAG-72). We report here a dichotomy in the expression of TAG-72 in carcinoma biopsy material versus carcinoma cell lines. While 44% (25 of 56) of human breast carcinoma and 80% (16 of 20) of colon carcinoma biopsies express TAG-72 as assayed by radioimmunoassay or immunohistochemistry, only one of 25 breast cancer cell lines [MCF-7 (one variant)] and one of 18 colon cancer cell lines (LS-174T) express this antigen. Furthermore, TAG-72 expression in these two cell lines was shown to be a property of a low percentage of cells within each culture. Attempts to enhance TAG-72 expression in LS-174T cells by propagation on extracellular matrix proteins, such as collagen, laminin, and fibronectin, or in serum-containing or serum-free, hormone-supplemented medium proved unsuccessful. A pronounced increase in TAG-72 expression was observed, however, when the LS-174T cells were grown under culture conditions which promote three-dimensional growth. LS-174T cells grown in spheroid or suspension cultures demonstrated a 2- to 7-fold increase in TAG-72 antigen expression, while those grown on agar plugs demonstrated a 10-fold increase. When the LS-174T cell line was injected into athymic mice to generate tumors, the level of TAG-72 antigen increased over 100-fold, to levels comparable to those seen in the metastatic tumor masses from patients. Thus, spatial configuration of carcinoma cell populations is shown to influence the expression of a tumor-associated antigen and the subsequent surface binding of monoclonal antibody B72.3. The implications of these findings in the potential utility of monoclonal antibodies for the in vivo detection and destruction of carcinoma masses are discussed.