Abstract P6-08-17: Pregnancy associated breast cancer: Evaluating maternal outcomes. A multicentre study

Background

Pregnancy associated breast cancer (PABC) is defined as breast cancer (BC) diagnosed during the gestational period (GP) or in the first year postpartum (PP). Despite its infrequent occurrence, the incidence of PABC appears to be rising due to the increasing propensity for women to delay childbirth. We have established the first combined prospective and retrospective registry study of PABC in Ireland to examine specific clinicopathological characteristics, treatments and maternal outcomes. We present the retrospective findings to date.

Methods

We performed a retrospective multicentre observational study of patients (pts) with PABC treated in the eight Irish cancer centres from August 2001 to March 2017. Data extracted included information on pt demographics, tumour biology, staging, treatment administered and maternal outcomes. Standard biostatistical methods were used for analysis.

Results

111 PABC patients were identified. Sixty pts (54%) were diagnosed during the GP and 51 (46%) within 1 year PP. Median age at diagnosis was 36 years (yrs). Table 1 illustrates baseline characteristics. Two thirds of pts were node positive and a similar proportion had grade 3 pathology. Seventy pts (63%) were estrogen receptor (ER) positive, 36 (32%) HER2 positive, 25 (22%) triple negative. Twenty-two pts (20%) were metastatic at presentation. Seven pts (6%) had a known BRCA 1/2 mutation. The median OS (overall survival) and DFS (disease free survival) for the entire cohort was 107.4 and 94.2 months respectively (resp). There was no survival difference between those diagnosed during the GP versus PP. 5 yr DFS and OS was 68.6% and 69.2% resp. This compares unfavourably to results reported by the National Cancer Registry of Ireland in a similar age-matched BC population between 2000-2012 where the 5 yr OS was 86.5%. Variables in our study associated with poorer outcomes included younger age, tumour size, node positivity and lack of estrogen expression.

Baseline characteristics PABC patients (n=11) %(n)Diagnosed in GP (n=60) %(n)Diagnosed 1yr PP (n=51) %(n)p valueDemographic    Age at diagnosis3636(25-49)36(21-44)0.31Stage    I-II54(60)55(33)53(27)0.85III23(26)23(14)23(12)1IV20(22)18(11)22(11)0.81Unknown3(3)3(2)2(1)1Pathology    Grade 366(74)70(42)63(32)0.43Node positive66(73)68(41)63(32)0.55ER+/HER2-41(45)38(23)43(22)0.69ER+/HER2+23(25)28(17)16(8)0.17ER-/HER2+14(16)17(10)12(6)0.59Triple negative22(25)17(10)29(15)0.11Surgery    Breast conservation23(26)25(15)21(11)0.82Mastectomy56(63)57(34)59(30)0.84Adjuavnt/Neoadjuvant treatment    Chemotherapy73(81)77(46)69(35)0.39Anthracycline68(55)78(36)54(19)0.03Taxane89(72)93(43)83(29)0.16Anti HER2 agent21(23)18(11)24(12)0.63Endocrine therapy64(52)63(29)66(23)0.84Radiotherapy79(64)74(34)86(30)0.85Relapse in Stage I-III    Local relapse15(13)12(6)18(7)0.55Distant relapse24(21)22(11)25(10)0.80

Conclusions

PABC patients may have a poorer outcome. Our study reported higher rates of triple negative and HER2 positive breast cancer which are associated with more aggressive biology. Prospective evaluation of clinicopathological features, pharmacokinetics of treatments selected and maternal and fetal outcomes is imperative in this distinct pt group.

Citation Format: Prior L, Teo M, Greally M, Ward C, O'Leary C, Aslam R, Darwish W, Ahmed N, Watson G, Kelly D, Kiely L, Hassan A, Gleeson J, Featherstone H, Lim M, Murray H, Gallagher D, Westrup J, Hennessy B, Leonard G, Grogan L, Breathnach O, Horgan A, Coate L, O'Mahony D, Coate L, O'Reilly S, Gupta R, Keane M, Duffy K, O'Connor M, Kennedy J, McCaffrey J, Higgins M, Kelly C, Carney D, Gullo G, Crown J, Walshe J. Pregnancy associated breast cancer: Evaluating maternal outcomes. A multicentre study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-08-17.

Triad of trichomegaly, alopecia and male-pattern hair growth during treatment with erlotinib in non-small-cell lung cancer

INTRODUCTION

Description of the cutaneous side effects of erlotinib.

MATERIALS

Report with images of a single case.

METHODS

Case report and review of the literature.

CONCLUSION

Erlotinib is associated with significant cutaneous toxicity which should be recognised and managed appropriately.

The frequency, manifestations, and duration of prolonged cytopenias after first-line fludarabine combination chemotherapy

BACKGROUND

Fludarabine-based chemoimmunotherapy has well-recognised efficacy and short-term toxicity in the treatment of lymphoid malignancies. However, the presence and significance of prolonged cytopenias after completion of treatment have not been thoroughly quantified.

METHODS

Sixty-one patients receiving initial therapy with fludarabine-based regimens were categorised according to the presence of post-treatment cytopenias (haemoglobin <110-130 g/l depending on sex and age, neutrophils <2.0 x 10(9)/l, or platelets <140 x 10(9)/l) lasting >3 months.

RESULTS

Persistent cytopenias unrelated to persistent disease were found in 43% of patients. Cytopenias were associated with clinically important rates of infection and transfusion requirement (P = 0.03) and predicted for worse overall survival (61% versus 96% at 60 months, P = 0.05). Increasing age predicted for persistent cytopenias (P = 0.02), but the presence of pretreatment cytopenias and delivered dose intensity were not predictive. The median times to resolution of anaemia, neutropenia, and thrombocytopenia were 7, 9, and 10 months, respectively.

CONCLUSIONS

Cytopenias often persist >3 months after first-line fludarabine combination therapy and can lead to important clinical sequelae. Although cytopenias generally resolve over time, treating physicians should be aware of these factors when considering fludarabine combination chemotherapy and when documenting treatment response status in chronic lymphocytic leukaemia.

Merkel cell carcinoma metastasis to the iris in a 23 year old female

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine malignancy which predominantly affects elderly caucasians. The pathogenesis is poorly understood but ultraviolet light and immunosuppression have both been implicated. MCC most commonly arises on sun exposed areas of the head and neck or extremities and has a propensity for local recurrence and regional lymph node metastasis. It may present as a violaceous or non specific firm nodule or as a small plaque. Histological diagnosis can be difficult and electron microscopy or immunohistochemistry are frequently required in addition to light microscopy. Management is stage dependant and frequently involves wide surgical excision with or without chemotherapy or radiation therapy. Early diagnosis and complete surgical excision is associated with a favourable prognosis. However, aggressive tumours with regional recurrence or distant metastases result in a median survival of 9 months. Reports of primary MCC of the eyelids have been reported in the literature. Intra-ocular metastases to the choroid and ciliary body have also been reported.

Dynamic light scattering study of biaxial ordering in a thermotropic liquid crystal

Dynamic light scattering from orientational order fluctuations in a liquid crystalline tetrapode reveals successive, weakly first-order isotropic to uniaxial and uniaxial to biaxial nematic phase transitions. The order parameter relaxation rates exhibit temperature dependences consistent with Landau-de Gennes mean field theory. Combined with previous evidence of a second-order uniaxial-biaxial transition in a closely related tetrapode, the present study supports the existence of a nematic-nematic tricritical point in thermotropic liquid crystals.

A Comparison of Whole-Body MRI and CT for the Staging of Lymphoma

OBJECTIVE

Our objective was to compare whole-body MRI and CT for the staging of lymphoma.

CONCLUSION

Whole-body MRI represents an alternative to CT in the staging of lymphoma, with an ability to stage disease, identify lymph nodes greater than 1.2 cm, and the additional ability to evaluate for the presence or absence of disease spread to bone marrow. CT allows detection of more nodes (< 1.2 cm) than MRI but this does not alter tumor stage.

[Effects of thrombin peptides on wound healing and proliferation and migration of normal human epidermal keratinocyte (NHEK)]

OBJECTIVE

To define the effects of thrombin peptides on wound healing and NHEK proliferation and migration.

METHODS

A wound model was made with four 1.5 cm circular full thickness dermal excisions on the back of each Sprague-Dawley rat. 0.1 microgram (40 microliter) TP508 was applied to each circular excisional wound in 9 rats, the other 9 received saline only. Wound area was calculated with JAVA Jandel and IMAGE PRO software. NHEK945 proliferation was assessed by MTT assay and direct cell count with a Coulter Counter. Cell migration was determined by 48-well Boyden Chamber. Cells migrated onto the lower surface of the filter were assessed by a Chemi Imager 4000 Image Analyzer and expressed as spot density.

RESULTS

Wound area in rats treated with TP508 was 73.7% and 45.4% of saline control on day 7 and 14, respectively. NHEK945 proliferation was accelerated after adding thrombin and TP508. The spot density of migrated cells was 76.7 plus minus 13.8 in medium alone. After adding 1 microgram/ml of thrombin and 10 microgram/ml of TP508, the spot density was 104.4 plus minus 12.2 and 109.4 plus minus 14.6, respectively.

CONCLUSION

Results of this study suggest that both thrombin and TP508 have significant actions on wound healing and NHEK proliferation and migration, which is important in wound repair.

Mycosis fungoides bullosa simulating pyoderma gangrenosum

A patient with mycosis fungoides (MF) bullosa had a rapidly growing, painful necrotic mass on the left ankle which extended by peripheral bulla formation, clinically resembling pyoderma gangrenosum. Histopathology confirmed MF bullosa with both intraepidermal and subepidermal bulla formation.

Systemic inflammation induced by cardiopulmonary bypass: a review of pathogenesis and treatment

The acute respiratory distress syndrome (ARDS) is a severe alteration in lung structure and function that develops secondary to a traumatic stimulus. When ARDS develops following cardiopulmonary bypass (CPB) it is know as postpump syndrome (PPS). ARDS can be caused by a single massive insult ("hit"); however, sequential minor insults ("hits") are more common clinically. The concept of multiple sequential insults causing ARDS has been termed the "two-hit" model of ARDS. The purpose of this article is to summarize our studies testing the hypothesis that PPS is caused by multiple sequential insults. To confirm our hypothesis, we developed a porcine model of "two-hit" PPS. Our model was composed of sequential benign insults, with CPB as the "first hit" and low dose of endotoxin as the "second-hit." It is our hypothesis that the mechanism of PPS is CPB-induced priming of polymorphonuclear leukocytes (PMNs) ("first-hit") with subsequent PMN activation by a second insult ("second-hit") such as endotoxin. Our model confirms this clinically relevant postulate, and we provide strategies to disrupt the inflammatory cascade leading to PPS.

Quality-of-life measurement in advanced cancer: assessing the individual

PURPOSE

Despite the increasing importance of assessing quality of life (QoL) in patients with advanced cancer, relatively little is known about individual patient's perceptions of the issues contributing to their QoL. The Schedule for the Evaluation of Individual Quality of Life (SEIQoL) and the shorter SEIQoL-Direct Weighting (SEIQoL-DW) assess individualized QoL using a semistructured interview technique. Here we report findings from the first administration of the SEIQoL and SEIQoL-DW to patients with advanced incurable cancer.

PATIENTS AND METHODS

QoL was assessed on a single occasion using the SEIQoL and SEIQoL-DW in 80 patients with advanced incurable cancer.

RESULTS

All patients were able to complete the SEIQoL-DW, and 78% completed the SEIQoL. Of a possible score of 100, the median QoL global score was as follows: SEIQoL, 61 (range, 24 to 94); SEIQoL-DW, 60.5 (range, 6 to 95). Psychometric data for SEIQoL indicated very high levels of internal consistency (median r =.90) and internal validity (median R(2) = 0.88). Patients' judgments of their QoL were unique to the individual. Family concerns were almost universally rated as more important than health, the difference being significant when measured using the SEIQoL-DW (P =.002).

CONCLUSION

Patients with advanced incurable cancer were very good judges of their QoL, and many patients rated their QoL as good. Judgments were highly individual, with very high levels of consistency and validity. The primacy given to health in many QoL questionnaires may be questioned in this population. The implications of these findings are discussed with regard to clinical assessment and advance directives.

Multiple sequential insults cause post-pump syndrome

BACKGROUND

We hypothesize that post-pump syndrome (PPS) following cardiopulmonary bypass (CPB) can be caused by multiple minor insults and that the mechanism of PPS is a priming and subsequent activation of polymorphonuclear (PMN) leukocytes. In this study extensive pathophysiologic and morphometric assessment was undertaken in a porcine model of sequential insult PPS.

METHODS

Pigs were anesthetized, placed on a ventilator, instrumented for measurements of hemodynamic function, and separated into five groups: (1) Control (n = 4)--surgery only, (2) CPB (n = 4)--placed on femoral-femoral hypothermic (28 degrees C) bypass for 1 h, (3) LPS (n = 6)--underwent sham CPB followed by infusion of low dose endotoxin [E. coli lipopolysaccharide (LPS-1 microg/kg)], (4) Heparin + protamine + LPS (HP + LPS, n = 4)--were heparinized without CPB for 1 h, following which protamine and LPS were infused and (5) CPB + LPS (n = 8)--subjected to both CPB and LPS.

RESULTS

Only CPB + LPS resulted in acute respiratory distress typical of PPS as indicated by a significant decrease in PaO2 and increase in intrapulmonary shunt fraction (p<0.05). CPB + LPS significantly increased tissue density and the number of sequestered monocytes and PMNs (p<0.05) above all other groups. Alveolar macrophages (AM) increased equally in all groups receiving LPS.

CONCLUSIONS

CPB primes the inflammatory system causing pulmonary PMN sequestration without lung injury. Exposure to an otherwise benign dose of endotoxin results in activation of the sequestered PMNs causing PPS. This study confirms that PPS can be caused by multiple minor insults.

Aerosolized surfactant improves pulmonary function in endotoxin-induced lung injury

Surfactant dysfunction is a primary pathophysiologic component in patients with adult respiratory distress syndrome (ARDS). In this study we tested the efficacy of aerosolized surfactant (Sf ) replacement in a severe lung injury model of endotoxin-induced ARDS. Twenty-one certified healthy pigs were anesthetized, surgically prepared for measurement of hemodynamic and lung function, then randomized into one of four groups: (1) control (n = 5), surgical instrumentation only; (2) lipopolysaccharide (LPS) (n = 6), infused with Escherichia coli LPS (100 microgram/kg) without positive end- expiratory pressure (PEEP) and ventilated with a nonhumidified gas mixture of 50% N2O and 50% O2; (3) LPS + PEEP (n = 4), infused with LPS, placed on PEEP (7.5 cm H2O), and ventilated with a humidified gas mixture; and (4) LPS + PEEP + Sf (n = 6), infused with LPS, placed on PEEP, and ventilated with aerosolized Sf (Infasurf, ONY, Inc.). All animals were studied for 6 h. Arterial PO2 significantly decreased in both the LPS and LPS + PEEP groups (LPS + PEEP = 74 +/- 19 mm Hg; LPS = 74 +/- 19 mm Hg, p < 0.05) while venous admixture (Q S/Q T) increased in these groups (LPS + PEEP = 43.3 +/- 3.9%; LPS = 47.7 +/- 11%, p < 0.05) as compared with the control group. PEEP + Sf reduced the fall in PO2 (142 +/- 20 mm Hg) and rise in Q S/Q T (15.1 +/- 3.6%) caused by LPS. Delayed induction of PEEP (2 h following LPS) did not significantly improve any parameter over the LPS group without PEEP in this ARDS model. LPS without PEEP (3.4 +/- 0.2 cells/6,400 micrometer2) caused a marked increase in the total number of sequestered leukocytes in the pulmonary parenchyma as compared with the control group (1.3 +/- 0.1 cells/6,400 micrometer2). LPS + PEEP + Sf (2.3 +/- 0.2 cells/6,400 micrometer2) significantly decreased while LPS + PEEP significantly increased (4.0 +/- 0.2 cells/6,400 micrometer2) the total number of sequestered leukocytes as compared with the LPS without PEEP group. In summary, aerosolized surfactant replacement decreased leukocyte sequestration and improved oxygenation in our porcine model of endotoxin-induced lung injury.

Molecular biology of lung cancer

Lung cancer is a major cause of mortality worldwide and the overall survival rate has not improved significantly in the past 20 years. Of the more than 150,000 new cases of lung cancer diagnosed in Europe every year, less than 10% of patients can be cured and enjoy long-term survival. The role of tobacco smoking as a cause of lung cancer has been conclusively established. Early diagnosis of lung cancer, based on conventional screening procedures using sputum cytology and chest radiography, has been so far unable to decrease lung cancer mortality. We discuss here the possibility that novel, more specific molecular markers, beside providing new understanding of the process of lung carcinogenesis, may also constitute new tools for early diagnosis allowing for screening of high-risk individuals, determination of prognosis, and identification of innovative treatments.

Expression of multidrug resistance-associated protein (MRP) in brain microvessel endothelial cells

Multidrug resistance-associated protein (MRP) is a recently identified drug efflux transport system that actively transports organic acids and selected glucuronide or glutathione conjugates out of the cell. The current study presents, for the first time, both functional and biochemical data demonstrating the presence of MRP in the brain microvessel endothelial cells that form the blood-brain barrier (BBB). Using known MRP inhibitors, such as indomethacin and probenecid, fluorescein accumulation in primary cultured bovine brain microvessel endothelial cell (BBMEC) monolayers was significantly enhanced compared to control. The specificity of the MRP inhibitors on cellular fluorescein accumulation was confirmed using both MRP positive (Panc-1) and MRP negative (KBv) cell lines. Furthermore, western blot analysis using a specific antibody for MRP (MRPm6) and RT-PCR studies using a complementary sequence probe for human MRP demonstrate the expression of MRP in BBMEC. Previous studies have demonstrated the significance of the P-glycoprotein drug efflux transporter in the BBB. Given its function as a drug efflux transport system, it is anticipated that MRP in the BBB will also have an important role in limiting the exposure of the brain to many endogenous and exogenous compounds, including both toxic and therapeutic agents.

Primary hepatic lymphoma in a man with chronic hepatitis C

We report the case of a middle-aged man who presented de novo with abdominal pain and hepatomegaly and was found to have positive serology for hepatitis C and subsequently a primary hepatic lymphoma. An increased incidence of primary hepatocellular cancer is well characterized in both cirrhotic and non-cirrhotic cases of chronic hepatitis C. The relationship between chronic hepatitis C and primary hepatic lymphoma remains obscure. It has been established that hepatitis C can sustain the clonal B-cell expansion that occurs in associated cryoglobulinaemia, and hepatitis C RNA has been detected within extrahepatic lymphoma tissue. Viral aetiologies for lymphoma are well characterized, such as Epstein-Barr virus (EBV) and human T-cell leukaemia virus (HTLV) I and II. Existing models of chronic infection causing lymphoma within the gastrointestinal tract include that of Helicobacter pylori and mucosa-associated lymphoid tumour of the stomach. Given the relatively low frequency of occurrence it may be prudent to perform a retrospective analysis on past cases of primary hepatic lymphoma in order to determine whether or not hepatitis C was present.

NCI-Navy Medical Oncology Branch cell line data base

The cell line data base described in this paper includes both clinical information about the patients from whom the cell lines were derived and information about the in vitro analyses performed of the cell lines. The cell line data base has evolved as a part of a systematic effort by a research group at the NCI since 1976 to generate human cell lines as biological tools to study cancer and other diseases. The cell lines were generated from clinical specimens obtained as part of a series of Institutional Review Board-approved clinical protocols. The preponderance of the data is on lung cancer cell lines, though a broad range of other cancers are represented. A bank of over 300 human cell lines including cancer cell and in some instances autologous B-lymphoblastoid cells from the NCI-VA and NCI-Navy Medical Oncology Branch are reposited at the American Type Culture Collection. The cell lines are available for the research community. The entire data base is available on the American Type Culture Collection Web Site (WWW:http:@www.atcc.org/).

Infusional cyclophosphamide, doxorubicin and etoposide in HIV-related non-Hodgkin's lymphoma: a follow-up report of a highly active regimen

Based on our prior data suggesting a therapeutic advantage for infusional administration of cyclophosphamide (C), doxorubicin (D), and etoposide (E) in patients with relapsed and resistant non-Hodgkin's lymphoma (NHL), we administered C (750 mg/m2), D (50 mg/m2), and E (240 mg/m2) via continuous intravenous infusion over 96 hours as first line therapy for 21 patients with intermediate- or high-grade non-Hodgkin's lymphoma associated with human immunodeficiency virus (HIV) infection. Treatment was repeated every 28 or more days. The median CD4 count of the study group was 87/ul, and the median serum lactate dehydrogenase was 383 IU/L. Extranodal disease, lymphomatous marrow involvement, and lymphomatous meningitis were present at diagnosis in 90%, 33%, and 10% of patients, respectively. Complete response (CR) occurred in 13 patients (62%, 95% confidence intervals 41%, 81%) and partial response occurred in five patients (24%). The estimated median survival of the study group was 18.0 months. Hematologic toxicity required dose reduction for 47% of cycles and for 79% of patients who received at least two cycles. The mean dose intensity for C, D, and E were 73%, 70%, and 73% of the intended dose intensity, respectively. Opportunistic infection included oral/esophageal candidiasis (N = 7), herpes labialis (N = 3), pulmonary Mycobacterium avium-intracellulare (N = 1), candidemia (N = 1), pneumonitis (N = 1), and disseminated aspergillosis than resulted in a single treatment-related death (5%). Treatment resulted in a significant decrease in the CD4+ lymphocytes, as well as total lymphocytes, T lymphocytes, and CD8+ lymphocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Resection of an intracardiac metastasis from malignant teratoma of the testis

Nonseminomatous germ cell testicular neoplasm is a disease cured primarily by platinum-based combination chemotherapy. Operation is reserved for those patients who continue to harbor residual masses after chemotherapy. Locoregional lymph nodes and lungs are common sites for residual deposits. Intracardiac metastases are very rare. We report a case of successful resection of bilateral lung and single intracardiac secondary deposits from a malignant teratoma, treated by orchidectomy 6 years previously.

Treatment of advanced non-small cell lung cancer with very high-dose cisplatin combined with etoposide and mitomycin C

BACKGROUND

Treatment options for advanced non-small-cell lung cancer are inadequate. There remains a critical need for more effective systemic therapies.

METHODS

Forty-one patients with advanced non-small-cell lung cancer were treated on a 28-day cycle with a very high-dose, cisplatin-based three-drug regimen. A treatment cycle consisted of an intravenous (IV) injection of cisplatin 100 mg/m2 on days 1 and 8; etoposide 60 mg/m2 IV over 30 minutes on days 1, 2, 8, and 9 (cycles 1 and 3 only); and mitomycin C 8 mg/m2 IV bolus on day 1 (cycles 2 and 4 only) (PEM regimen).

RESULTS

The median dose intensity of cisplatin delivered was 49 mg/m2/wk, or 98% of the planned dose. One patient achieved a complete response and 16 patients a partial response or regression, yielding an overall objective response rate of 41%. The median duration of response was 21 weeks. Median survival of all patients was 38 weeks. Neurologic toxicity was dose limiting. The frequency of peripheral neuropathy and ototoxicity was directly related to cumulative cisplatin dose. In five patients, a progressive peripheral neuropathy developed after discontinuation of cisplatin. Hematologic toxicity also was significant.

CONCLUSIONS

This very high-dose, cisplatin-based chemotherapy regimen has appreciable activity in advanced non-small-cell lung cancer. In comparison with previous reports on the use of very high-dose cisplatin alone, however, this combination appears at best to be only marginally more active, to confer no additional survival advantage, and to be considerably more toxic.

Anthropometric measurements of adolescent and professional classical ballet dancers

This study examined anthropometric measures of 83 female adolescent students attending the Boston Ballet summer program and 15 professional dancers from the Boston Ballet Company. Thirty-one were in the least advanced level (group A), 38 were in the moderately advanced level (group B) and 14 were in the most advanced level (group C). The adolescent dancers devoted between 17 and 23 hours per week in dance training, while professional dancers spent 39.2 hours per week in class and rehearsals. Compared to normative data, the dancers tended to be tall and slim. The skinfold, diameter, and circumference measurements were found to be very similar among groups A, B and C, and between group C and the company members. The somatograms demonstrated that the ballet dancers had relatively smaller upper arms and larger calves and ankles compared with the reference female. The data from this study suggest that the body type characteristics associated with professional classical ballet dancers are already apparent in the pre-professional adolescent dancers.

18th Sir Hans Krebs lecture. Knowledge-based protein modelling and design

A systematic technique for protein modelling that is applicable to the design of drugs, peptide vaccines and novel proteins is described. Our approach is knowledge-based, depending on the structures of homologous or analogous proteins and more generally on a relational data base of protein three-dimensional structures. The procedure simultaneously aligns the known tertiary structures, selects fragments from the structurally conserved regions on the basis of sequence homology, aligns these with the 'average structure' or 'framework', builds on the loops selected from homologous proteins or a wider database, substitutes sidechains and energy minimises the resultant model. Applications to modelling an homologous structure, tissue plasminogen activator on the basis of another serine proteinase, and to modelling an analogous protein, HIV viral proteinase on the basis of aspartic proteinases, are described. The converse problem of ab initio design is also addressed: this involves the selection of an amino acid sequence to give a particular tertiary structure, in this case a symmetrical domain of two Greek-key motifs.

Knowledge based modelling of homologous proteins, Part I: Three-dimensional frameworks derived from the simultaneous superposition of multiple structures

An approach is described for modelling the three-dimensional structure of a protein from the tertiary structures of several homologous proteins that have been determined by X-ray analysis. A method is developed for the simultaneous superposition of several protein molecules and for the calculation of an 'average structure' or 'framework'. Investigation of the convergence properties of this method, in the case of both weighted and unweighted least squares, demonstrates that both give a unique answer and the latter is robust for an homologous family of proteins. Multi-dimensional scaling is used to subgroup of the proteins with respect to structural homology. The framework calculated on the basis of the family of homologous proteins, or of an appropriate subgroup, is used to align fragments of the known protein structures of high sequence homology with the unknown. This alignment provides a basis for model building the tertiary structure. Different techniques for using the framework to model the mainchain of various globins and an immunoglobulin domain in the structurally conserved regions are investigated.

Heterogeneity of cell surface antigen expression of human small cell lung cancer detected by monoclonal antibodies

Using immunohistochemistry, radiobinding, and indirect immunofluorescence assays, seven distinct cell surface antigens, detected by monoclonal antibodies, were analyzed for the degree of homogeneity or heterogeneity of antigen expression on a panel of human small cell lung cancers. The panel included 7 tumors taken directly from patients, 21 established cell lines (9 of which were derived from different metastatic sites of 3 patients), and 33 clonal derivatives of 3 lines. With all assays, considerable heterogeneity of antigen expression between tumors from different patients was observed. In both fresh tumors and in cell lines, as well as in cell lines established from different metastatic sites in an individual patient, we observed intratumor heterogeneity finding antigen positive and negative cells and variation in antigenic density, by immunohistochemistry and indirect immunofluorescence assays. Antigenic expression was not cell cycle dependent. In addition, when cell lines or patient samples expressing antigen positive and antigen negative tumor cells were cloned, heterogeneity of antigenic expression was still present in the clonal lines. This suggests that either the expression of the antigen was not heritable and/or the ability to regenerate antigenic heterogeneity is an intrinsic property of the tumor cells. The heterogeneity of antigen expression on lung cancer cells has significant implications for the use of these and other monoclonal antibodies in the study and therapy of lung cancer.