Development and validation of AI-assisted transcriptomic signatures to personalize adjuvant chemotherapy in patients with pancreatic ductal adenocarcinoma.

BACKGROUND: After surgical resection of pancreatic ductal adenocarcinoma (PDAC), patients are predominantly treated with adjuvant chemotherapy, commonly consisting of gemcitabine (GEM)-based regimens or the modified FOLFIRINOX (mFFX) regimen. While mFFX regimen has been shown to be more effective than GEM-based regimens, it is also associated with higher toxicity. Current treatment decisions are based on patient performance status rather than on the molecular characteristics of the tumor. To address this gap, the goal of this study was to develop drug-specific transcriptomic signatures for personalized chemotherapy treatment. PATIENTS AND METHODS: We used PDAC datasets from preclinical models, encompassing chemotherapy response profiles for the mFFX regimen components. From them we identified specific gene transcripts associated with chemotherapy response. Three transcriptomic artificial intelligence signatures were obtained by combining independent component analysis and the least absolute shrinkage and selection operator-random forest approach. We integrated a previously developed GEM signature with three newly developed ones. The machine learning strategy employed to enhance these signatures incorporates transcriptomic features from the tumor microenvironment, leading to the development of the 'Pancreas-View' tool ultimately clinically validated in a cohort of 343 patients from the PRODIGE-24/CCTG PA6 trial. RESULTS: Patients who were predicted to be sensitive to the administered drugs (n = 164; 47.8%) had longer disease-free survival (DFS) than the other patients. The median DFS in the mFFX-sensitive group treated with mFFX was 50.0 months [stratified hazard ratio (HR) 0.31, 95% confidence interval (CI) 0.21-0.44, P < 0.001] and 33.7 months (stratified HR 0.40, 95% CI 0.17-0.59, P < 0.001) in the GEM-sensitive group when treated with GEM. Comparatively patients with signature predictions unmatched with the treatments (n = 86; 25.1%) or those resistant to all drugs (n = 93; 27.1%) had shorter DFS (10.6 and 10.8 months, respectively). CONCLUSIONS: This study presents a transcriptome-based tool that was developed using preclinical models and machine learning to accurately predict sensitivity to mFFX and GEM.

Baseline nutritional status is prognostic factor after definitive radiochemotherapy for esophageal cancer.

Identify prognostic factors for survival and patterns of treatment failure after definitive radiochemotherapy for esophageal cancer. Between 2003 and 2006, 143 patients with squamous cell carcinoma and adenocarcinoma of the esophagus were retrospectively reviewed. Median age was 65 years (42-81). Median radiation dose was 62.5 Gy (38-72) with 1.8-2 Gy fraction. Median follow-up was 20.8 months (2.8-92.4). Three and 5-year local recurrence-free survival rates were 58.3% and 50.9%. In univariate analysis, traversable esophageal stricture was a prognostic factor. Three, 5-year locoregional recurrence-free survival rates were 42.4% and 34.9%. In multivariate analysis, traversable esophageal stricture and stage < IIB were independent prognostic factors. Three and 5-year disease-free survival rates were 30.5% and 25.9%. In multivariate analysis, Nutritional Risk Index (NRI) ≥ 97.5 and performance status (PS) = 0 were independent prognostic factors. Median, 3, and 5-year overall survival rates were 22.1 months, 34.4%, and 19.8%. In multivariate analysis, independent prognostic factors were NRI ≥ 97.5 and PS = 0. Median survival times for the NRI classes (no denutrition, moderate and severe denutrition) were 29.5, 19.7, and 12 months (P = 0.0004), respectively. A major impact of baseline NRI was found in terms of survival; it should be included in future prospective trials.

Efficacy of immunotherapy in mismatch repair-deficient advanced colorectal cancer in routine clinical practice. An AGEO study.

BACKGROUND: Immunotherapy demonstrated remarkable efficacy in metastatic colorectal cancers (mCRCs) with mismatch repair deficiency (MMRd)/microsatellite instability (MSI). However, data regarding efficacy and safety of immunotherapy in the routine clinical practice are scarce. PATIENTS AND METHODS: This is a retrospective, multicenter study aiming to evaluate efficacy and safety of immunotherapy in routine clinical practice and to identify predictive markers for long-term benefit. Long-term benefit was defined as progression-free survival (PFS) exceeding 24 months. All patients who received immunotherapy for an MMRd/MSI mCRC were included. Patients who received immunotherapy in combination with another known effective therapeutic class agent (chemotherapy or tailored therapy) were excluded. RESULTS: Overall, 284 patients across 19 tertiary cancer centers were included. After a median follow-up of 26.8 months, the median overall survival (mOS) was 65.4 months [95% confidence interval (CI) 53.8 months-not reached (NR)] and the median PFS (mPFS) was 37.9 months (95% CI 30.9 months-NR). There was no difference in terms of efficacy or toxicity between patients treated in the real-world or as part of a clinical trial. Overall, 46.6% of patients had long-term benefit. Independent markers associated with long-term benefit were Eastern Cooperative Oncology Group-performance status (ECOG-PS) 0 (P = 0.025) and absence of peritoneal metastases (P = 0.009). CONCLUSIONS: Our study confirms the efficacy and safety of immunotherapy in patients with advanced MMRd/MSI CRC in the routine clinical practice. ECOG-PS score and absence of peritoneal metastases provide simple markers that could help identify patients who benefit the most from this treatment.

Reverse Osmosis Membrane Zero Liquid Discharge for Agriculture Drainage Water Desalination: Technical, Economic, and Environmental Assessment.

Agricultural drainage water (ADW) represents a potential source for fresh water after receiving appropriate treatments to satisfy the water quality requirements. Desalination of ADW with medium salinity and moderate contamination with organic and inorganic chemical pollutants could provide a techno-economically feasible approach for facing water scarcity in arid areas. The current work presents a conceptual zero liquid discharge ADW desalination system proposed to treat 300,000 m3/d. The system is based on pretreatment to remove impurities harmful to desalination by staged reverse osmosis (RO) membrane. The brine from the last RO stage is treated via thermal vapor compression followed by evaporation in solar ponds to recover more fresh water and salts of economic value. The essential technical features of the proposed system components are formulated. The proposed system components and its technical and economic indicators are deduced using available software for water pretreatment, RO membrane, desalination, thermal desalination, and solar evaporation ponds. The system provides total distilled water recovery of about 98% viz. 294,000 m3/d in addition to recovered salts of 245,000 t/y. The net cost of water production amounts to USD 0.46 /m3. The environmental considerations of the system are addressed and advantages of applying zero liquid discharge system are elucidated.

Characterization of a premeiotic germ cell-specific cytoplasmic protein encoded by Stra8, a novel retinoic acid-responsive gene.

The full-length cDNA corresponding to Stra8, a novel gene inducible by retinoic acid (RA) in P19 embryonal carcinoma cells, has been isolated and shown to encode a 45-kD protein. Both Stra8 mRNA and protein were induced in cells treated by all-trans and 9-cis retinoic acids. Two-dimensional gel analysis and dephosphorylation experiments revealed that the two stereoisomers of RA differentially regulate the phosphorylation status of the Stra8 protein, which was shown to exist in differently phosphorylated forms. Subcellular fractionation and immunocytochemistry studies showed that the Stra8 protein is cytoplasmic. During mouse embryogenesis, Stra8 expression was restricted to the male developing gonads, and in adult mice, the expression of Stra8 was restricted to the premeiotic germ cells. Thus, Stra8 protein may play a role in the premeiotic phase of spermatogenesis.

Continuation versus discontinuation of first-line chemotherapy in patients with metastatic squamous cell oesophageal cancer: A randomised phase II trial (E-DIS).

PURPOSE: The role of chemotherapy has not been established in the treatment of metastatic squamous cell oesophageal cancer (mESCC). PATIENTS AND METHODS: E-DIS is a discontinuation trial, aimed at estimating efficacy, quality of life and safety of chemotherapy continuation (CT-CONT) in patients with mESCC who are free from progression after a selection phase of chemotherapy. The primary end-point was overall survival. RESULTS: Sixty-seven patients were randomised. The 9-month survival rate was 50% (85% confidence interval [CI]: 37-62%) and 48% (85% CI: 35-60%) in the CT-CONT arm and in the chemotherapy discontinuation (CT-DISC) arm, respectively. The time until definitive deterioration of the global health status (European Organisation for Research and Treatment of Cancer [EORTC] core quality of life questionnaire) was 6.6 months (95% CI: 3.3-12.4) for the CT-CONT arm and 4.2 months (95% CI: 2.9-6.3) for the CT-DISC arm, with a hazard ratio (HRCT-DISC/CT-CONT) = 1.44 (95% CI: 0.82-2.53). We observed a beneficial trend in favour of CT-CONT (HR > 1) for most dimensions, including an improvement for three dimensions (dysphagia, eating and oesophageal pain) of the EORTC Oesophageal Cancer Module QLQ-OES18. CONCLUSION: CT-CONT provides an overall survival rate that is similar to CT-DISC. E-DIS trial provides valuable data to support shared decision-making between physicians and patients regarding CT-CONT/DISC.

Assessment of left ventricular ejection fraction with late-systolic and mid-diastolic cardiac phases using multi-slice computed tomography.

INTRODUCTION: Multi-slice computed tomography (MSCT) is an accurate tool for the assessment of left ventricular ejection fraction (LVEF). However, in order to reduce radiation dose, prospective acquisition protocols are currently used, in which the end-systole and end-diastole are not scanned. Our aim was to study the accuracy of the assessment of LVEF using fixed late-systolic and mid-diastolic cardiac phases compared with echocardiography. METHODS: MSCT-derived LVEF was measured with off-line commercially available software packages, and compared with echocardiography-derived LVEF using the Simpson's method. LVEF was categorized as normal vs. abnormal (50% cut-off) and was also analyzed as a quantitative parameter. Bland-Altman plots and Pearson correlations were used for inter-technique comparisons. RESULTS: 58 patients were included. The sensitivity and specificity of fixed-phase MSCT when compared with echocardiography for detection of LVEF ≤50% was 79% (95% CI = 65-89%) and 43% (10-82%). Misclassification was associated with older age (68 ± 12 vs. 54 ± 13 years, p < 0.01), faster heart rate (79 ± 14 vs. 68 ± 10 bpm, p = 0.01), and LV hypertrophy (86% vs. 52%, p = 0.03). The quantitative comparison revealed no correlation (r = 0.095, p = 0.478) and a significantly different LVEF (median[IQR], 57.0[50.5-63.1]% vs. 61.0[57.3-64.3]%, p = 0.03). The observed bias between the two methods was -3.7% with broad limits of agreement (±25.5%). CONCLUSIONS: Fixed-phase MSCT assessment using late-systole and mid-diastole agreed in defining normal and abnormal LVEF in 76% of patients when compared with echocardiography. Quantitation of LVEF by this method yielded significantly lower values of LVEF and showed no correlation. Thus, accurate quantitation of LVEF by MSCT requires the acquisition of end-systolic and end-diastolic phases.

A new mouse member of the Wnt gene family, mWnt-8, is expressed during early embryogenesis and is ectopically induced by retinoic acid.

We have identified a novel mouse Wnt genc using a cDNA differential screening procedure for retinoic-acid-induced transcripts in P19 embryonal carcinoma cells. Sequence analysis showed that this gene represents the first murine Wnt-8 (mWnt-8) gene reported to date. The expression of the mWnt-8 gene, which is rapidly induced by retinoic acid in P19 and embryonic stem cells, appears to be restricted to early stages of mouse embryogenesis. mWnt-8 transcripts are first detected in the posterior region of the epiblast of early primitive streak-stage embryos. As gastrulation proceeds, mWnt-8 expression spreads into the embryonic ectoderm up to a sharp rostral boundary at the base of the developing headfolds. mWnt-8 is also transiently expressed in the newly formed mesoderm. mWnt-8 expression is rapidly down-regulated during early somitogenesis, the latest detectable expression domains corresponding to the presumptive fourth rhombomere and the caudal region of the neural plate. The expression pattern of mWnt-8 is clearly distinct from those of other murine Wnt genes expressed during gastrulation, but shows striking similarities with that of the chicken Cwnt-8C gene. We also show that mWnt-8 expression is ectopically induced in the rostral neural plate in response to RA exposure of presumitic (7-7.5 days post coitum) cultured mouse embryos.

AP-2.2, a novel gene related to AP-2, is expressed in the forebrain, limbs and face during mouse embryogenesis.

Using a differential subtractive hybridization cloning procedure we have recently identified the AP-2.2 gene as a novel early retinoic acid-induced gene in murine P19 embryonal carcinoma cells. We have also shown that the AP-2.2 protein, which is highly related to the AP-2 transcription factor, can activate transcription when bound to an AP-2 consensus binding site [Oulad-Abdelghani et al. (1995) Mol. Cell. Biol., submitted]. We report here the in situ hybridization pattern of expression of AP-2.2 transcripts during mouse embryogenesis. At 7.5 days post-coitum, AP-2.2 transcripts were detected in the boundary region between neural plate and surface ectoderm, as well as in extra-embryonic tissues. By 8.0-8.5 gestational days, AP-2.2 transcripts appeared to be expressed in premigratory and migrating neural crest cells. Over the following days, the AP-2.2 gene displayed region-restricted expression in the facial mesenchyme, especially around the embryonic mouth cavity and the nasal cavities, as well as in the surface ectoderm, nasal and oral epithelia. AP-2.2 RNA was also specifically expressed in the presumptive cortical region of the forebrain vesicles. AP-2.2 transcripts were restricted to the distal mitotic area (the 'progress zone') of the limb buds and of the genital bud. AP-2.2 expression also appeared to be specific for primordial germ cells in the genital ridges. Thus, the AP-2.2 gene is expressed in several embryonic areas whose development can be affected by retinoids, such as the forebrain, face and limb buds.

Differential expression of retinoic acid-inducible (Stra) genes during mouse placentation.

Several retinoid binding proteins and nuclear receptors are specifically expressed in murine placenta. However, little is known about molecular events and target genes regulated by retinoids during placentation. Here, we report that several retinoic acid-inducible (Stra) genes, originally isolated by a differential screening procedure, exhibit specific expression patterns in mouse placental tissues. Three Stra genes, including the ephrinB1 receptor tyrosine kinase ligand, are prominently expressed in the regions of exchanges between maternal and embryonic circulations, i.e. the yolk sac and/or the labyrinthine zone of the mature placenta. The Meis2 homeobox gene appears to be specifically expressed in maternally-derived cell populations. Three other Stra genes, including the AP-2-related gene AP-2gamma, are differentially expressed in the trophoblastic cell lineage. Thus, retinoids may regulate various signaling pathways in specific placental cell-types.

Phosphorylation of the retinoic acid receptor-alpha by protein kinase A.

The phosphorylation of retinoic acid receptor-alpha 1 (RAR alpha 1) by PKA was investigated both in vitro and in vivo. We show that bacterially expressed RAR alpha 1 is phosphorylated in vitro by protein kinase A (PKA) at the unique serine residue 369 located in the C-terminal end of the E region. We also show that RAR alpha 1 overexpressed in COS-1 cells is phosphorylated on multiple serine residues and that phosphorylation at serine 369 occurs only when COS-1 cells are cotransfected with PKA or treated with forskolin. RAR alpha 1 mutants were constructed in which serine 369 was replaced by an alanine (S369A) or a glutamic acid (S369E) residue. Comparison of the tryptic phosphopeptide patterns of wild type and mutated RAR alpha 1 overexpressed in COS-1 cells allowed us to confirm that serine 369 is the unique phosphorylation site for PKA in cultured cells. The DNA-binding efficiency of RAR alpha/retinoid X receptor-alpha (RXR alpha) heterodimers was enhanced in vitro by the S369E mutation. However, in transfected RAC65 cells, the same S369E mutation did not affect the ligand-dependent transcriptional activation by RAR alpha 1 of reporter genes containing a retinoic acid (RA)-response element. In contrast, the S369A mutation slightly decreased both DNA binding and the efficiency of PKA to enhance RA-induced transactivation by RAR alpha 1. Finally, we show that endogenous RAR alpha is also phosphorylated in vivo at serine 369 in forskolin-treated F9 cells, supporting the idea that phosphorylation of RARs at this site is involved in the modulation of the RA-induced differentiation of F9 cells by (Bu)2cAMP.

[A urachus cyst revealing a torpid Crohn's disease in a young adult with chronic fever]. / Kyste de l'ouraque révélateur d'une maladie de Crohn torpide chez un adulte jeune atteint d'une fievre nue chronique.

INTRODUCTION: This case report describes a rare situation in which a superinfected cyst of the urachus complicated initially unknown and inactive Crohn's disease. CASE: A 21-year-old man presented a chronic fever finally attributed to a superinfected urachal cyst. Six months after ablation of the cyst, progressive Crohn's disease was diagnosed. DISCUSSION: The association of Crohn's disease and a superinfected urachal cyst is extremely rare. The case reported here is original in two aspects: the slowly progressive Crohn's disease was diagnosed after its complication; the superinfection developed through local bacterial translocation (ileal loop adjacent to the urachal cyst).

Stra3/lefty, a retinoic acid-inducible novel member of the transforming growth factor-beta superfamily.

We report the structure, chromosomal localization and expression features of Stra3, a novel mouse gene whose expression is upregulated by retinoic acid in P19 embryonal carcinoma cells. The Stra3 cDNA sequence, which encodes a novel member of the TGF-beta superfamily, corresponds to, but extends more 3' than the recently published lefty sequence (Meno et al., 1996, Nature 381:151-155). The Stra3/lefty protein, which exhibits characteristics of secreted proteins, is synthesized as a precursor of 42 kDa and secreted after cleavage, suggesting that it may function as an intercellular signaling molecule. There are four exons in the Stra3/lefty gene and its 5' flanking region contains, among other putative regulatory elements, an unusual retinoid response element consisting of two half sites arranged as a palindrome, with an 8 base pairs spacer. We also show that Stra3/lefty is ectopically induced in the endodermal and ectodermal layers following in vivo administration of retinoic acid to gastrulating mouse embryos.

Laparoscopic Interrupted Muscular Arch Repair in Recurrent Unilateral Inguinal Hernia Among Children.

PURPOSE: We present a procedure of suturing the transversus abdominis muscular arch to the ileopubic tract laparoscopically in order to repair recurrent unilateral pediatric inguinal hernia (PIH). PATIENTS AND METHODS: Twenty-five children with recurrent unilateral PIH were treated during a 5-year period in a tertiary academic center. All cases were subjected to laparoscopic hernia repair and discharged the next morning. Sutures were placed from the muscular arch to the ileopubic tract, avoiding the spermatic vessels and duct, in an interrupted manner using 2/0-3/0 polypropylene (Prolene®; Ethicon, Somerville, NJ) or polyglactin 910 (Vicryl®; Ethicon) sutures. In 4 cases, a rectangular purse-string-like suture was added to narrow the internal ring defect. Operative findings and postoperative results and complications were assessed. The patients were followed up for a period that ranged between 6 and 60 months. RESULTS: There were 23 boys and 2 girls. Operative age ranged between 18 months and 15 years. Three or four sutures were placed in each case. In 4 cases, an additional rectangular purse-string-like suture was added. Operative time ranged between 35 and 70 minutes, and there was no conversion. Mild scrotal edema was reported in 4 cases and port-site infection in 2 cases; all cases were treated conservatively. One case of recurrence among boys was reported, but there was no case of testicular atrophy. Cosmetic outcomes were excellent. CONCLUSIONS: Laparoscopic interrupted muscular arch repair is a feasible and safe technique in the reconstruction of the inguinal canal in recurrent unilateral PIH. Larger studies and long-term follow-up are needed to support our encouraging results.

[Definitive chemoradiotherapy for esophageal cancer: 66Gy versus 50Gy, a retrospective study]. / Chimioradiothérapie exclusive pour cancer de l'œsophage : comparaison entre 66Gy et 50Gy, une étude rétrospective.

PURPOSE: To compare the influence of radiation dose, high dose versus standard dose, on survival for patients with esophageal carcinomas treated with definitive radiochemotherapy. PATIENTS AND METHODS: Between 2003 and 2006, 143 consecutive patients with squamous-cell carcinoma and adenocarcinoma, clinical stage I to IVA, treated in two different institutions were retrospectively reviewed, 83 patients had received more than 50.4Gy, median dose 66Gy (50.7-72Gy) and 60 less than or equal to 50.4Gy, median dose 50Gy (38-50.4Gy). RESULTS: Median age was higher in high dose group (67.6 versus 61.7 years). Nutritional status and stage were better in high dose group with a lower weight loss (5.1 versus 7.9%), a higher body mass index (25.7 versus 22.9), more N0 patients (60.2 versus 31.7%) and less stage III (27.7 versus 63.3%). Median follow up was 20.8 months (2.8-92.4 months), and 64.9 months (4.2-92.4 months) for the 33 surviving patients. No statistically significant difference was shown for local/locoregional control, disease-free survival. Overall survival at 2-, 3- and 5-year and median survival was respectively 44.7%, 36.8%, 19.1% and 21.2 months in high dose group and 50.8%, 31.6%, 20.7% and 24.6 months in standard dose group (P=0.9). CONCLUSION: No difference was found between the two groups in terms of local/distant control and overall survival. A prospective randomised study is needed.

Sensitivity derivatives for flexible sensorimotor learning.

To learn effectively, an adaptive controller needs to know its sensitivity derivatives--the variables that quantify how system performance depends on the commands from the controller. In the case of biological sensorimotor control, no one has explained how those derivatives themselves might be learned, and some authors suggest they are not learned at all but are known innately. Here we show that this knowledge cannot be solely innate, given the adaptive flexibility of neural systems. And we show how it could be learned using forms of information transport that are available in the brain. The mechanism, which we call implicit supervision, helps explain the flexibility and speed of sensorimotor learning and our ability to cope with high-dimensional work spaces and tools.

Multiple and time-scheduled in situ DNA delivery mediated by beta-cyclodextrin embedded in a polyelectrolyte multilayer.

The basic premise of gene therapy is that genes can be used to produce in situ therapeutic proteins. The controlled delivery of DNA complexes from biomaterials offers the potential to enhance gene transfer by maintaining an elevated concentration of DNA within the cellular microenvironment. Immobilization of the DNA to the substrate to which cells adhere maintains the DNA in the cell microenvironment for subsequent cellular internalization. Here, layer-by-layer (LBL) films made from poly(L-glutamic acid) (PLGA) and poly(L-lysine) (PLL) containing DNA were built in the presence of charged cyclodextrins. The biological activities of these polyelectrolyte films were tested by means of induced production of a specific protein in the nucleus or in the cytoplasm by cells in contact with the films. This type of coating offers the possibility for either simultaneous or sequential interfacial delivery of different DNA molecules aimed at cell transfection. These results open the route to numerous potential applications in patch vaccination, for example.

Restricted expression of a novel retinoic acid responsive gene during limb bud dorsoventral patterning and endochondral ossification.

Using a differential substractive hybridization cloning procedure we have recently identified Stra6 as a novel retinoic acid-induced gene in murine P19 embryonal carcinoma cells. The putative amino acid sequence of Stra6 shows no similarity with previously characterised proteins. We report here the pattern of expression of Stra6 transcripts during mouse limb development as revealed by in situ hybridization. In 8.5-9.0 days post-coitum (dpc) embryos, Stra6 was expressed in the lateral plate mesenchyme prior to limb bud outgrowth. By 9.5 dpc, expression was restricted to the proximal and dorsal forelimb bud mesoderm. Over the next 2 gestational days, Stra6 expression was specific of the dorsal mesoderm of the undifferentiated forelimb and hindlimb buds with the exception of their distal-most region or progress zone. A novel proximal-ventral expression domain appeared, however, by 11.0-11.5 dpc. Stra6 also remained expressed in the flank mesoderm. From 11.5-13.5 dpc, Stra6 expression was restricted to the superficial mesenchyme surrounding the chondrogenic blastemas, and progressively extended until the distal extremities of the limbs upon disappearance of the progress zone. Progressive restriction of Stra6 expression to perichondrium and developing muscles was seen at 13.5-14.5 dpc. Upon the initiation of endochondral ossification (15.5-16.5 dpc), Stra6 expression was limited to the area of perichondrium opposing cells of high metabolic and proliferative activity (the elongation zone). We suggest that Stra6 may play a role in early dorsoventral limb patterning and later in the control of endochondral ossification.

AP-2.2: a novel AP-2-related transcription factor induced by retinoic acid during differentiation of P19 embryonal carcinoma cells.

A 2.8-kb cDNA encoding a new transcription factor (AP-2.2) has been cloned from mouse P19 embryonal carcinoma cells, in which the corresponding mRNA begins to accumulate 30 min after retinoic acid (RA) addition. The predicted protein is 449 amino acids long and exhibits approximately 65% overall identity with other AP-2-related proteins (human AP-2, mouse AP-2alpha and beta). A 96-amino-acid-long sequence, which is almost fully conserved between all these proteins, corresponds to the previously characterized human AP-2 DNA binding domain. Expression of AP-2.2 in Escherichia coli generated a protein that formed a specific complex with the AP-2 recognition site GCCN3GGC. AP-2.2 activated transcription from a reporter gene containing an AP-2 DNA binding site and acted synergistically with RARalpha to activate transcription from the CRABPII gene promoter. Transcriptional activation required the AP-2.2 amino-terminal region that contains a domain rich in proline and glutamine residues. The pattern of AP-2.2 expression in adult tissues, which is distinct from that of AP-2alpha, is essentially restricted to male and female gonads, to most if not all the squamous epithelia, and to several exocrine glands.