Deqin Sun

p63 is essential for regenerative proliferation in limb, craniofacial and epithelial development.

The p63 gene, a homologue of the tumour-suppressor p53 (refs 1–5), is highly expressed in the basal or progenitor layers of many epithelial tissues. Here we report that mice homozygous for a disrupted p63 gene have major defects in their limb, craniofacial and epithelial development. p63 is expressed in the ectodermal surfaces of the limb buds, branchial arches and epidermal appendages, which are all sites of reciprocal signalling that direct morphogenetic patterning of the underlying mesoderm. The limb truncations are due to a failure to maintain the apical ectodermal ridge, a stratified epithelium, essential for limb development. The embryonic epidermis of p63 −/− mice undergoes an unusual process of non-regenerative differentiation, culminating in a striking absence of all squamous epithelia and their derivatives, including mammary, lacrymal and salivary glands. Taken together, our results indicate that p63 is critical for maintaining the progenitor-cell populations that are necessary to sustain epithelial development and morphogenesis.

Ki-67, cyclin E, and p16ink4 are complimentary surrogate biomarkers for human papilloma virus-related cervical neoplasia

Prior studies of Ki-67, cyclin E, and p16 expression have suggested that these biomarkers may be preferentially expressed in cervical neoplasia. This study examined and compared the distribution of staining for these three antigens in 1) normal and reactive epithelial changes, 2) diagnostically challenging cases (atypical metaplasia and atypical atrophy), 3) squamous intraepithelial lesions (SIL), and 4) high-and low-risk human papilloma virus (HPV) type-specific SIL. One hundred four epithelial foci from 99 biopsies were studied, including low-grade squamous intraepithelial lesions (LSIL; 24), high-grade squamous intraepithelial lesions (HSIL; 36), mature or immature (metaplastic) squamous epithelium (29), and atrophic or metaplastic epithelium with atypia (15). Cases were scored positive for Ki-67 expression if expression extended above the basal one third of the epithelium, for cyclin E if moderate to strong staining was present, and for p16 if moderate to strong diffuse or focal staining was present. HPV status was scored by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of extracted DNA. Immunohistochemical findings were correlated with histologic and viral data. Overall, a histologic diagnosis of SIL correlated strongly with all of the biomarkers used (p <0.001). Positive scores for Ki-67, cyclin E, and p16 were seen in 68.4%, 96.7%, and 100% of LSILs and 94.7%, 91.6%, and 100% of HSILs, respectively. Positive predictive values of these three biomarkers for HPV were 82.4%, 89.5%, and 91.4%, respectively. The positive predictive value for HPV of either cyclin E or p16 was 88.7%. Strong diffuse staining for p16 was significantly associated with high-risk HPV-associated lesions. Normal or reactive epithelial changes scored positive for the three biomarkers in 7.7%, 8.0%, and 12%, respectively. Limitations in specificity included minimal or no suprabasal staining for Ki-67 in immature condylomas and occasional suprabasal staining of reactive epithelial changes (10%), diffuse weak nuclear cyclin E staining in some normal or metaplastic epithelia, and diffuse weak basal p16 staining and occasional stronger focal positivity in normal epithelia. Ki-67, cyclin E, and p16 are complementary surrogate biomarkers for HPV-related preinvasive squamous cervical disease. (Because cyclin E and p16 are most sensitive for LSIL and HSIL [including high-risk HPV], respectively, use of these biomarkers in combination for resolving diagnostic problems, with an appreciation of potential background staining, is recommended.)

Discrimination of complete hydatidiform mole from its mimics by immunohistochemistry of the paternally imprinted gene product p57KIP2.

The p57 KIP2 protein is a cell cycle inhibitor and tumor suppressor encoded by a strongly paternally imprinted gene. We explored the utility of p57 KIP2 as a diagnostic marker in hydatidiform mole, a disease likely the result of abnormal dosage and consequent misexpression of imprinted genes. Using a monoclonal antibody on paraffin-embedded, formalin-fixed tissue sections, the authors evaluated p57 KIP2 expression in normal placenta and in 149 gestations including 59 complete hydatidiform moles, 39 PHMs, and 51 spontaneous losses with hydropic changes. p57 KIP2 was strongly expressed in cytotrophoblast and villous mesenchyme in normal placenta, all cases of partial hydatidiform moles (39 of 39) and all spontaneous losses with hydropic changes (51 of 51). In contrast, p57 KIP2 expression in cytotrophoblast and villous mesenchyme was absent or markedly decreased in 58 of 59 complete hydatidiform moles. In all gestations p57 KIP2 was strongly expressed in decidua and in intervillous trophoblast islands, which served as internal positive controls for p57 KIP2 immunostaining. p57 KIP2 immunohistochemistry can reliably identify most cases of complete hydatidiform mole irrespective of gestational age and is thus a useful diagnostic adjunct, complementary to ploidy analysis, in the diagnosis of hydatidiform mole.

h-Caldesmon expression effectively distinguishes endometrial stromal tumors from uterine smooth muscle tumors

Distinction of endometrial stromal neoplasms from cellular smooth muscle tumors of the uterus is sometimes difficult. Immunohistochemistry is often not helpful because muscle actins and desmin are expressed in both neoplasms. This studys goal was to determine whether h-caldesmon, a smooth muscle-specific isoform of a calcium, calmodulin, and actin binding protein, could effectively distinguish endometrial stromal tumors from uterine smooth muscle tumors. The authors analyzed immunohistochemical expression in 24 endometrial stromal neoplasms (21 sarcomas and three nodules), 29 leiomyosarcomas, 32 leiomyomas (10 “usual,” 14 cellular leiomyoma, and eight “highly cellular” types), 40 myometria, and 25 endometria. h-Caldesmon was diffusely positive in all myometria, leiomyomata, and leiomyosarcomas. Of note, 16 leiomyosarcomas (55%) were positive for h-caldesmon in more than 50% of tumor cells. In five “highly cellular” leiomyomas, h-caldesmon expression was markedly decreased or absent in areas morphologically resembling endometrial stromal tumors, raising the possibility that these tumors may be mixed smooth muscle–endometrial stromal neoplasms. In contrast, h-caldesmon expression was absent in all endometria and endometrial stromal neoplasms apart from accompanying small vessels. Desmin was diffusely positive in all myometria and leiomyomata. The fraction of cells expressing desmin was greater than that of h-caldesmon in only 10% of leiomyosarcomas. Focal desmin expression was also present in eight of 25 (32%) endometria and 12 of 24 (50%) endometrial stromal neoplasms. h-Caldesmon appears to be a more sensitive and specific marker of smooth muscle differentiation in the uterus than desmin and may be a useful tool for distinguishing and classifying uterine mesenchymal tumors.

Stratified mucin-producing intraepithelial lesions of the cervix: adenosquamous or columnar cell neoplasia?

BACKGROUND: Squamous (CIN) and glandular (ACIS) intraepithelial lesions often coexist in the same cervical specimen. However, a less common and little studied variant consists of a stratified epithelium resembling CIN in which conspicuous mucin production is present (Stratified Mucin-producing Intraepithelial LEsions (SMILE). This report describes the phenotypic characteristics of the SMILE, its associated lesions, and its immunophenotype. METHODS: Eighteen SMILEs were identified by the presence of conspicuous cytoplasmic clearing or vacuoles in lesions otherwise resembling CIN. The morphologic spectrum of SMILEs was detailed; including associated intraepithelial and invasive cervical neoplasms. In addition, selected cases were stained for muci-carmine, markers of squamous cell/reserve cell differentiation (keratin-14 and p63), and proliferative activity (Mib-1). RESULTS: Stratified neoplastic epithelial cells with a high Mib-1 index and a rounded or lobular contour at the epithelial-stromal interface characterized SMILEs. In contrast to CIN, in which mucin droplets are confined to surface cells, mucin was present throughout the epithelium, varying from indistinct cytoplasmic clearing to discrete vacuoles. SMILEs were distinguished from benign metaplasia by nuclear hyperchromasia and a high Mib-1 index. All but three coexisted with either a squamous (CIN) or glandular (ACIS) precursor lesion. Nine of nine coexisting invasive carcinomas contained glandular, adenosquamous differentiation, or both. SMILEs stained negative for keratin-14 and variably for p63. When present, staining with p63 was confined to basal areas of SMILEs and was absent in areas of columnar differentiation. CONCLUSIONS: SMILEs are unusual cervical intraepithelial lesions best classified as variants of endocervical columnar cell neoplasia based on immunophenotype. The distribution and immunophenotype of SMILEs are consistent with a neoplasm arising in reserve cells in the transformation zone. The coexistence of a wide spectrum of intraepithelial and invasive cell phenotypes suggests that SMILEs are a marker for phenotypic instability, emphasizing the importance of identifying SMILEs and ensuring a complete examination of specimens containing this unusual precursor lesion.

Atypical Glandular Cells of Undetermined Significance Outcome Predictions Based on Human Papillomavirus Testing

Cases of atypical glandular cells (AGC) diagnosed on liquid-based preparations were culled from a 3-year period. When available, residual cellular material was analyzed for human papillomavirus (HPV) by polymerase chain reaction and correlated with cytologic and histologic (biopsy) outcome. Of 178,994 cytologic cases, 187 (0.1045%) contained AGC compared with 8,740 (4.8828%) atypical squamous cells (ASC) for an AGC/ASC ratio of 0.021. HPV results and follow-up were available for 108 specimens from 106 patients. Depending on the end-point (histologic/cyto-logic), the sensitivity range of HPV testing for significant cervical disease (high-grade squamous intraepithelial lesion [SIL], adenocarcinoma in situ [ACIS], invasive carcinoma) was 83% with a specificity range of 78% to 82%, a positive predictive value of 57% to 61%, and a negative predictive value of 91% to 95%. Fifteen false-positive results included concurrent ASC or low-grade SIL, ASC on follow-up cytology, and previous ACIS with a negative follow-up cone biopsy result. Noncervical glandular neoplasia (including atypical endometrial hyperplasia) was confirmed in 13 cases (1 recurrent), only 2 of which scored positive for HPV. HPV-positive AGC has a substantially higher positive predictive value for significant disease than ASC (61% vs historic 20%) and merits consideration in the triage of patients with atypical endocervical cells not otherwise specified. However, noncervical or other HPV-negative glandular neoplasia must be considered in all patients with AGC, particularly older patients.

Allelic loss in human papillomavirus-positive and -negative vulvar squamous cell carcinomas

Vulvar squamous cell carcinoma (VSCC) is a biologically and morphologically diverse disease, consisting of human papillomavirus (HPV)-positive and -negative tumors that differ in their morphological phenotypes and associated vulvar mucosal disorders. This study analyzed the frequencies of allelic loss (loss of heterozygosity (LOH)) in HPV-positive and -negative VSCCs to identify potential targets for the study of preinvasive diseases, to determine whether HPV status influenced patterns of LOH, and to determine whether these patterns differed from HPV-positive tumors of another genital site, cervical squamous cell carcinomas (CSCC). DNA extracted from microdissected archival sections of two index tumors, one each HPV negative and positive, was analyzed for LOH at 65 chromosomal loci. Loci scoring positive with either sample were included in an analysis of 14 additional cases that were also typed for HPV. Frequencies of LOH at loci were computed in a panel of HPV-positive and -negative VSCCs. Twenty-nine loci demonstrated LOH on the initial screen and were used to screen the remaining 14 tumors. High frequencies of LOH were identified, some of which were similar to a prior karyotypic study (3p, 5q, 8p, 10q, 15q, 18q, and 22q) and others of which had not previously been described in VSCC (1q, 2q, 8q, 10p, 11p, 11q, 17p, and 21q). With the exception of 5q and 10p, there were no significant associations between frequency of LOH and HPV status in VSCC. LOH at 3p and 11q were frequent in both VSCC and CSCC; however, allelic losses at several sites, including 5q, 8q, 17p, 21q, and 22q, were much more common in VSCC. VSCCs exhibit a broad range of allelic losses irrespective of HPV status, with high frequencies of LOH on certain chromosomal arms. This suggests that despite their differences in pathogenesis, both HPV-positive and -negative VSCCs share similarities in type and range of genetic losses during their evolution. Whether the different frequencies of LOH observed between VSCC and CSCC are real or reflect differences in stage and/or tumor size remains to be determined by further comparisons. The role of these altered genetic loci in the genesis of preinvasive vulvar mucosal lesions merits additional study.

Atypical immature metaplastic-like proliferations of the cervix: Diagnostic reproducibility and viral (HPV) correlates

Although some immature squamous lesions (papillary immature metaplasias) of the cervix have been described and associated with human papillomaviruses (HPV), nonpapillary atypical immature squamous proliferations (AISPs) are a poorly defined entity and range from atypical reactive metaplasias to squamous intraepithelial lesions resembling immature metaplasia. This study examined the diagnostic reproducibility of AISPs and their relationship to HPV nucleic acids. Forty-four diagnostically problematic AISPs were studied. Based on nuclear density (crowding), chromasia, variation (anisokaryosis) in nuclear size, and surface cytoplasmic maturation, cases were independently scored by 2 observers as (1) probably reactive (Rx), (2) not otherwise specified (NOS), and (3) squamous intraepithelial lesion (SIL). Extracted archival DNA was scored for HPV by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Interobserver reproducibility (kappa statistic) and HPV correlates (chi square) were computed. Approximately one third of cases were classified in each category by the observers. Interobserver reproducibility was excellent (0.80), poor (0.23), and fair to good (0.41) for a diagnosis of Rx, NOS, and SIL, respectively. Differences in HPV DNA positivity between Rx and SIL were significant for both observers (5.8% to 6.7% v 38.4% to 50.0%, respectively); however, differences between NOS and SIL (30.7% to 42.8% v 38.4% to 50.0%) were not, even when cases were limited to those in which both observers agreed (28.6% v 37.5%). By light microscopy, AISPs exceeding the threshold for presumed reactive changes (NOS or SIL) are a morphologically heterogeneous group that defy precise classification. Furthermore, their histopathologic appearance, even when there is diagnostic agreement, does not consistently correlate with their HPV status. The laboratory management of AISPs should take into account the uncertainty of this diagnosis.

Papillary immature metaplasia (immature condyloma) of the cervix : A clinicopathologic analysis and comparison with papillary squamous carcinoma

Papillary immature metaplasia (PIM) is a variant of human papillomavirus (HPV) 6 or 11 infection. PIM resembles an immature metaplasia but has filiform papillae, variable cytological atypia, and, frequently, extension into the endocervical canal. Because the unusual morphology and presentation of PIM may cause confusion between this and other benign and malignant papillary neoplasms, we conducted a clinicopathologic analysis of PIM and compared expression of Ki-67 between PIM, condyloma, and papillary carcinoma. Data on patient age, duration of the lesions, and procedures, including cone biopsy, were obtained. The distribution and intensity of staining for Ki-67 in the epithelium was recorded and compared with both condyloma and papillary carcinoma. HPV typing was performed by polymerase chain reaction (PCR) and restriction fragment length pleomorphism analysis (RFLP). Ten of 13 PIMs were HPV 6/11 positive. Three cases contained areas closely resembling condyloma. Eleven cone biopsies were performed on nine cases. Three were found to have a coexisting high-grade squamous intraepithelial lesion that was either HPV 6/11 negative or contained another HPV type. All PIMs displayed variable staining for Ki-67 with a low index of staining in the mid and upper epithelial layers. In contrast, areas of condyloma had significantly stronger staining in areas with viral cytopathic effect (koilocytosis). Six papillary carcinomas were analyzed and displayed moderate to diffuse staining, including staining of the superficial cell nuclei. PIM is a distinct pathological subset of cervical condyloma that frequently is managed by cone biopsy and may persist. The marked reduction in Ki-67 staining in superficial cell layers distinguishes PIM from some condylomata and most HSILs and papillary carcinomas. Immunostaining thus may be helpful in distinguishing PIM from papillary carcinoma, although the differentiation of the two is best made on morphological grounds.

Managing Atypical Squamous Cells of Undetermined Significance (ASCUS): Human Papillomavirus Testing, ASCUS Subtyping, or Follow-Up Cytology?

Colposcopically directed biopsy finds high-grade squamous intraepithelial lesion (HSIL) in the histologic specimen of 5% to 15% of cervical smears taken from women with a diagnosis of atypical squamous cells of undetermined significance (ASCUS). This study was designed to investigate the ability of human papillomavirus (HPV) testing, ASCUS subtyping, and follow-up cytology to predict the presence of HSIL in the cervical smear. The study material consisted of 918 liquid-based cervical cytologic samples (ThinPrep test, Cytec Corp, Boxborough, MA) collected in a single pathologic laboratory between 1997 and 2000. HPV testing was carried out in 704 of the samples that had sufficient cytologic material remaining for follow-up cytologic examination, including 105 with a normal diagnosis, 426 cases of ASCUS, 126 with low-grade squamous intraepithelial lesion (LSIL), and 47 with HSIL. The cervical samples of 91% of the women with HSIL, 88% of those with LSIL, and 49% of those with ASCUS were positive for all HPV types, but only 27% of those with normal cervical cytology contained all HPV types. When only high-risk HPV types were considered, the percentage of positivity for normal samples dropped to 19% and the percentage for HSIL increased to 96%. The ASCUS category was further sorted into ASCUS, favor reactive (AFR); ASCUS, not otherwise specified (ANOS); ASCUS, favor LSIL (AFLS); and ASCUS, favor HSIL (AFHS). Both high- and low-risk HPV types were found in AFR and ANOS samples slightly more frequently than in normal samples. High- and low-risk HPV types were found in AFLS far more frequently than in normal smears but slightly less than for LSIL. This pattern continued with the progression from LSIL to AFHS and from AFHS to HSIL. Three hundred eighty-six women of the 704 women had a year or more of follow-up data available, including a biopsy or other tests within 1 year of the cervical smear. Eight women with an initial diagnosis of ASCUS progressed to HSIL (3.4%). The presence of HPV was detected in the samples of all of these women, including high-risk HPV in seven of the eight, yielding a sensitivity of 88% and a specificity of 73% for high-risk HPV testing in predicting the development of HSIL in women with ASCUS. The positive predictive value for high-risk HPV testing was 11%. The sensitivity of any type HPV testing was 100%, but the specificity was only 48%. In all, 64% of the women for whom follow-up data were available regressed to normal. Compared with the 3.4% of ASCUS women who were found to have HSIL, 11% of the positive high-risk HPV patients developed HSIL. A designation of AFHS led to HSIL in 25% of the women with an initial diagnosis of ASCUS. Only 1.1% of the ASCUS women designated AFR later developed HSIL.