Immunophenotypic analysis of the p53 gene in non-melanoma skin cancer and correlation with apoptosis and cell proliferation

Immunohistochemical detection of p53 and pp53 Ser392 in canine hemangiomas and hemangiosarcomas located in the skin

Background

p53 protein is essential for the regulation of cell proliferation. Aberrant accumulation of it usually occurs in cutaneous malignancies. Mutant p53 is detected by immunohistochemistry because it is more stable than the wild-type p53. However, post-translational modifications of p53 in response to ultraviolet radiation are important mechanisms of wild-type p53 stabilization, leading to positive staining in the absence of mutation. The aims were: 1) to analyze the immunohistochemical expression of p53 and phospho-p53 Serine³⁹² in canine skin endothelial tumours; and 2) to determine if any relationship exists between p53 and phospho-p53 Serine³⁹² overexpression and cell proliferation.

Results

p53 and phospho-p53 Serine³⁹² immunolabeling was examined in 40 canine cutaneous endothelial tumours (13 hemangiomas and 27 hemangiosarcomas). Their expression was associated with tumour size, hemangiosarcoma stage (dermal versus hypodermal), histological diagnosis and proliferative activity (mitotic count and Ki-67 index). Statistical analysis revealed a significant increase of p53 immunoreactivity in hemangiosarcomas (median, 74.61%; interquartile range [IQR], 66.97–82.98%) versus hemangiomas (median, 0%; IQR, 0–20.91%) (p < .001) and in well-differentiated hemangiosarcomas (median, 82.40%; IQR, 66.49–83.17%) versus hemangiomas (p = .002). Phospho-p53 Serine³⁹² immunoreactivity was significantly higher in hemangiosarcomas (median, 53.80%; IQR, 0–69.50%) than in hemangiomas (median, 0%; IQR, 0.0%) (p < .001). Positive correlation of the overexpression of p53 and phospho-p53 Serine³⁹² with mitotic count and Ki-67 index was found in the cutaneous vascular tumours (p < .001). The Ki-67 index of the hemangiomas (median, 0.50%; IQR, 0–2.80%) was significantly lower than that of the hemangiosarcomas (median, 34.85%; IQR, 23.88–42.33%) (p < .001), and that specifically of well-differentiated hemangiosarcomas (median, 24.60%; IQR, 15.45–39.35%) (p = .001). Immunolabeling of 18 visceral hemangiosarcomas showed that the p53 (median, 41.59%; IQR, 26.89–64.87%) and phospho-p53 Serine392 (median, 0%; IQR, 0–22.53%) indexes were significantly lower than those of skin (p = .001; p = .006, respectively).

Conclusions

The p53 and phospho-p53 Serine³⁹²overexpression together with high proliferative activity in hemangiosarcomas versus hemangiomas indicated that p53 might play a role in the acquisition of malignant phenotypes in cutaneous endothelial neoplasms in dogs. The Ki-67 index may be useful in distinguishing canine well-differentiated hemangiosarcomas from hemangiomas.

Electrochemotherapy induces tumor regression and decreases the proliferative index in canine cutaneous squamous cell carcinoma

Canine cutaneous squamous cell carcinoma (cSCC) is the most common skin cancer in dogs, and, due to its low metastatic rate, local treatments, such as electrochemotherapy (ECT), promote disease control or even complete remission (CR). This study aimed to evaluate the gene and protein expression of Bcl-2 and Bcl-2 associated X protein (BAX), the proliferative index and clinical parameters in dogs with cSCC subjected to ECT. A prospective nonrandomized clinical study was performed using dogs with naturally occurring cSCC that was treated with ECT. Eighteen lesions from 11 dogs were selected. The tumor size at day 0 (D0) had no impact on survival or prognosis (P > 0.05). Tumor samples had a lower proliferative index after ECT (D21) than before ECT (P = 0.031). The survival of subjects with Ki67 values lower and higher than the Ki67 median value were not significantly different (P > 0.05). Regarding apoptotic markers, there were no significant differences in the gene and protein expression levels of BAX or Bcl-2 at D0 and D21 (P > 0.05) or in the overall survival of subjects with different levels of apoptotic markers. In conclusion, there was no change in BAX or Bcl-2 gene and protein expression in response to ECT at the time points evaluated, but ECT was able to reduce tumor volume and cellular proliferation in cSCC.

Contribution to characterization of skin field cancerization activity: morphometric, chromatin texture, proliferation, and apoptosis aspects

BACKGROUND

A skin field cancerization is a cutaneous area with subclinical changes resultant from chronic sun exposure, with a higher predisposition to development of pre-neoplastic and neoplastic lesions. So far, there are no well-defined objective parameters that can indicate their degree of activity.

OBJECTIVES

To describe and compare morphometric aspects and expression of factors related to apoptosis and cell proliferation in actinic keratosis (AK), in both photoexposed and photoprotected epidermis.

METHODS

A cross-sectional study of patients with actinic keratosis in the forearms, biopsied at two points: the actinic keratosis and the axillary region. The biopsies of the actinic keratosis, perilesional area, and axilla were evaluated through keratinocyte intraepithelial neoplasia (KIN), and immunohistochemistry of p53, survivin, and Ki67. Nuclear morphometry of basal layer cells was performed through digital image analysis: entropy, area, perimeter, Ra, fractal dimension, circularity, color intensity, and largest diameter.

RESULTS

There were 13 patients included and 38 actinic keratosis biopsied. In morphometry, 1039 nuclei were analyzed, of which 228 represented axillary skin, 396 demonstrated actinic keratosis, and 415 represented the perilesional area to the actinic keratosis. There was a significant difference (p<0.05) in all variables tested for the topographies evaluated. A significant correlation was identified between nucellar morphometric elements, KIN, proliferation markers, and apoptosis. Joint patterns of p53, Ki67, and KIN discriminated the topographies sampled.

STUDY LIMITATIONS

This was a cross-sectional study with a small number of patients.

CONCLUSIONS

There are patterns of proliferation, resistance to apoptosis, and different cellular morphometrics between photoprotected skin and photoexposed skin. The joint expression of p53, Ki67, and KIN can characterize skin field cancerization activity.

Mucosal human papillomavirus detection and TP53 immunohistochemical expression in non-melanoma skin cancer in Tunisian patients

BACKGROUND

Several studies have reported the oncogenic role of human papillomavirus (HPV) in non-melanoma skin cancer (NMSC) carcinogenesis. Considering that HPV could affect tumor protein 53 (TP53) degradation via E6 oncoprotein, we evaluated the expression of TP53 according to HPV infection and E6 expression.

METHODS

Biopsy specimens from 79 NMSCs (28 squamous cell carcinomas, 21 keratoacanthomas and 30 basal cell carcinomas) were enrolled. Nested PCR was used to detect mucosal HPV (mHPV) DNA. Genotyping was performed by reverse line hybridization. Expression of TP53 and E6 was evaluated by immunohistochemistry.

RESULTS

mHPVs were detected in 34.2% (27/79) of NMSC, with 92.6% (25/27) of high-risk HPV (HR-HPV) types. HPV16-E6-positive expression was observed in all HPV16-positive samples. TP53 high expression was found in 51.4% (37/72) of specimens. In this group, 78.4% were HPV-negative (P = 0.014). TP53 expression was negative in 8/10 of HPV E6-positive specimens. Multivariate analysis showed that TP53 was associated with HPV infection independently of histopathologic type (P = 0.005).

CONCLUSION

This study showed a high prevalence of mHPV in NMSC. Active infections assessed by E6 expression are associated with loss of p53 function, highlighting the involvement of mHPV in NMSC carcinogenesis.

Interplay Between the Immunohistochemical Expression of P53 and the Proliferation Index in the Keratinocyte Tumors of the Skin

P53 is important for cell cycle regulation, and its overexpression is seen in malignant tumors. We examined correlation between p53 expression and cell proliferation, and its role in the pathogenesis of keratinocyte skin tumors. We used biopsies from patients with squamous cell carcinoma, actinic keratosis and keratoacanthoma. We examined crosssections stained with HE and using anti-cytokeratin, antip53 and anti-Ki67 antibodies.

Expression of p53 is found in 87, 85% of SCC, in 83. 3% of AK and 13. 4% KA. The high index of p53 expression was higher in SCC and AK compared to KA. We also observed a positive correlation between the expression of p53 and localization of the tumors. The largest proportion of subjects with AK and SCC has a high index of p53 expression on photoexposed region. We also observed that p53 expression correlates with age whereby in AK p53 expression increases with age. The high index of proliferation is most frequent in SCC and KA. Also at AK we found a strong correlation between a moderate proliferation index and tumor localization in photoexposed region. Between the proliferation index and p53 expression we observed a significant positive correlation only in SCC.

Proliferation index and the expression of p53 are useful for the differentiation of precursor keratinocyte lesions and skin carcinoma. High p53 expression has been associated with the aging and significantly correlates with the exposure to UV radiation in SCC and AK. High expression of p53 in AK and SCC supports the importance of this oncoprotein in carcinogenesis of the skin.

Genital basal cell carcinoma, a different pathogenesis from sun-exposed basal cell carcinoma? A case-control study of 30 cases

BACKGROUND

Genital basal cell carcinoma (BCC) accounts for <1% of all BCCs. We aimed to elucidate the pathogenesis of genital BCC.

METHODS

We retrospectively evaluated cases of pathologically diagnosed genital BCC between 1990 and 2016 in an Asian tertiary referral center. The control group was composed of consecutive cases, from 2016, of BCCs occurring in sun-exposed areas. Presence of human papillomavirus (HPV) was evaluated by polymerase chain reaction (PCR). Immunohistochemical p16 and p53 staining was performed and analyzed.

RESULTS

We found 33 genital BCCs (33/1837, 1.8%) over 26 years. The mean follow-up duration was 30.0 ± 33.2 months. Genital BCCs had a larger size (14.05 vs 8.92 mm, P = 0.014), more common presence of ulcers (61.3% vs 32.0%, P = 0.035), shorter epidermal p53 clone (0.33 vs 1.20 mm, P = 0.007), and high p53 expression levels. Most cases (29/30, 96.7%) showed negative or faint spotty p16 staining. Patient age, tumor depth, presence of pigment, or histology subtype did not differ significantly. Thirty genital BCCs were negative for HPV.

CONCLUSIONS

HPV infection is mostly likely not involved in genital BCC pathogenesis. A greater level of p53 expression in genital BCCs implicates pathways other than ultraviolet (UV)-specific p53 mutations in their pathogenesis.

Bioconjugated graphene oxide-based Raman probe for selective identification of SKBR3 breast cancer cells

In this article, we demonstrate the use of bio-conjugated 2D graphene oxide (bio-GO) nanostructure to probe breast cancer cell (SKBR3) with excellent discrimination over other types of circulating tumor cells. We distinctly observed that bio-GO nanostructure targets and bind SKBR3 cell selectively in the cell mixture. Longer incubation of SKBR3 cell with bio-GO causes Raman signal "turn off" when excited with 532 nm laser. This is attributed to penetration of the bio-GO through the plasma membrane of the cell by generating transient hole. Extraction of GO after cell digestion also support the internalization rubric of 2D graphene through cell membrane. Our experimental data with the HaCaT healthy cell line, as well as with LNCaP prostate cancer cell line clearly demonstrated that this Raman scattering assay is highly selective to SKBR3. The mechanism of selectivity and the assay's response change have been verified and discussed utilizing fluorescence properties of GO and various other techniques. The experimental results open up a possibility of new label free Raman scattering assay, for reliable diagnosis of cancer cell lines by monitoring "turn-off" of the Raman signal from Bio-GO nanostructure.

The Significance of miR-34a Expression in Endometrial Carcinogenesis: Correlation With Expression of p16 and Ki-67 Proteins in Endometrial Cancers

Background:

A microRNA, miR-34a, plays a key role in inhibiting cellular transformation and carcinogenesis by controlling cell cycle regulation and cell proliferation in various human tumors. However, miR-34a has rarely been reported in endometrial cancer research in Korea. This study was undertaken to analyze miR-34a expression in simple endometrial hyperplasia and endometrial cancer, and to evaluate the relationship between expression of miR-34a and p16 and Ki-67 proteins in endometrial cancers.

Methods:

A retrospective study was carried out on 66 formalin-fixed, paraffin-embedded tissues with simple endometrial hyperplasia (31 cases) and endometrial cancer (35 cases) patients. These were analyzed for miR-34a expression by quantitative real-time PCR, and the expression of p16 and Ki-67 proteins in endometrial cancers was evaluated by immunohistochemistry.

Results:

The miR-34a expression level was lower in endometrial cancer tissues (−0.71 ± 3.90) than in simple endometrial hyperplasia tissues (2.68 ± 8.62). The endometrial hyperplasia tissues showed underexpression of miR-34a in 13 of the 31 cases (41.9%) while the endometrial cancer tissues showed underexpression of miR-34a in 24 of 35 cases (68.6%). Thus, miR-34a was significantly underexpressed in endometrial cancer tissues when compared endometrial hyperplasia tissues (P = 0.046). Overexpression of p16 was detected in 25 (71.4%) and Ki-67 immunoreactivity was detected in 27 (77.1%) of the 35 endometrial cancers. Although not statistically significant, the frequency of p16 and Ki-67 overexpression tended to be lower in the cases with miR-34a underexpression than in cases with miR-34a overexpression.

Conclusions:

These findings suggest that underexpression of miR-34a might be involved in endometrial carcinogenesis. Further studies are needed to define the relationship between miR-34a expression and tissue specific protein expression.

Effective blue light photodynamic therapy does not affect cutaneous langerhans cell number or oxidatively damage DNA

BACKGROUND

Photodynamic therapy (PDT) using aminolevulinic acid (ALA) with blue light or red light is effective for treating actinic keratoses (AKs). However, immunosuppression follows red light PDT, raising the spectre of skin cancer promotion in treated skin.

OBJECTIVE

To determine whether broad-area short incubation (BASI)-ALA-PDT using blue light immunosuppression immunosuppresses treated skin.

METHODS

Patients were evaluated clinically and by standardized facial biopsies of non-AK skin before, 24 hours and 1 month after customary blue light BASI-ALA-PDT. All biopsies were stained for markers of epidermal atypia and Langerhans cells (LCs); and at 24 hours to detect oxidative DNA damage.

RESULTS

Patients had an 81% reduction in AKs and slight improvement in clinical and histologic signs of photoaging after 1 month. The biopsied chronically photodamaged skin without clinically detectable AKs showed no effect of PDT on the LC number, distribution, or morphology; and no oxidative DNA damage, in contrast to the changes reported after customary red light PDT.

CONCLUSION

Customary blue light BASI-ALA-PDT does not affect the LC number or produce oxidative DNA damage, the sequelae of red light PDT responsible for immunosuppression in treated skin.

Brm inhibits the proliferative response of keratinocytes and corneal epithelial cells to ultraviolet radiation-induced damage

Ultraviolet radiation (UV) from sunlight is the primary cause of skin and ocular neoplasia. Brahma (BRM) is part of the SWI/SNF chromatin remodeling complex. It provides energy for rearrangement of chromatin structure. Previously we have found that human skin tumours have a hotspot mutation in BRM and that protein levels are substantially reduced. Brm−/− mice have enhanced susceptibility to photocarcinogenesis. In these experiments, Brm−/− mice, with both or a single Trp53 allele were exposed to UV for 2 or 25 weeks. In wild type mice the central cornea and stroma became atrophic with increasing time of exposure while the peripheral regions became hyperplastic, presumably as a reparative process. Brm−/−, Trp53+/−, and particularly the Brm−/− Trp53+/− mice had an exaggerated hyperplastic regeneration response in the corneal epithelium and stroma so that the central epithelial atrophy or stromal loss was reduced. UV induced hyperplasia of the epidermis and corneal epithelium, with an increase in the number of dividing cells as determined by Ki-67 expression. This response was considerably greater in both the Brm−/− Trp53+/+ and Brm−/− Trp53+/− mice indicating that Brm protects from UV-induced enhancement of cell division, even with loss of one Trp53 allele. Cell division was disorganized in Brm−/− mice. Rather than being restricted to the basement membrane region, dividing cells were also present in the suprabasal regions of both tissues. Brm appears to be a tumour suppressor gene that protects from skin and ocular photocarcinogenesis. These studies indicate that Brm protects from UV-induced hyperplastic growth in both cutaneous and corneal keratinocytes, which may contribute to the ability of Brm to protect from photocarcinogenesis.

Immunohistochemical evaluation of p53 and Ki67 expression in skin epithelial tumors

BACKGROUND AND AIMS

The cellular mechanisms responsible for initiating or limiting the tumors including skin types are of great importance. The p53 is a tumor-inhibiting gene which is believed to be defective in many malignant situations. Ki67 is a non-histonic protein which is mainly interfere with the proliferation and has many controlling effects during the cell cycle. Because of their importance in skin tumor cell growth, this study aimed at evaluating the p53 and Ki67 expression in skin epithelial tumors by immunohistochemical method.

MATERIALS AND METHODS

In a descriptive setting, 50 biopsy samples (30 basal cell carcinomas (BCCs), 10 squamous cell carcinomas (SCCs), 8 keratoacanthomas (KAs), and 2 trichoepitheliomas (TEs)) were immunohistochemically evaluated for p53 and Ki67 expression during a 14-month period. The incidence and expression rate of these two variables were separately reported in each group of samples.

RESULTS

The expression rate of p53 was 67.77% for the BCCs, 50.20% for the SCCs, and null for the KAs. For both TEs, it was 50%. The expression rate of Ki67 was 57.33% for the BCCs, 47.70% for the SCCs, 37.5% for the KAs, and 0.0% for TEs. The incidence of P53+ cells was 100% and 90% in the BCC and SCC samples, respectively. The both TEs were positive in this regard. The incidence of Ki67+ cells was 100% for the BCC, SCC, and KA samples. The both TEs were negative in this regard.

CONCLUSION

This study showed that the incidence rate of p53- and Ki67-positive cells is very high in skin malignant epithelial tumors. The expression rate of these two variables is comparable with reports in the literature. Further studies with large sample size are recommended to be carried out for KA and TE samples.

[Markers expression of cell proliferation and apoptosis in basal cell carcinoma]

BACKGROUND

- Basal cell carcinoma is the most common form of human cancer. Studies employing molecular and genetic biology techniques, associated with histomorphology, lead to the identification of risk factors in the development of more recurring and aggressive lesions. OBJECTIVE - To correlate markers expression of apoptosis (p53 and bcl-2) and cell proliferation (Ki-67 and PCNA) with histological indicators of tumor severity. METHODS - Five samples of the nodular, morpheaform and superficial types of carcinoma were studied, respectively.One control group with three lesion-free patients was also included in the study. The Mann-Whitney test was used to compare these markers expression with the manifestation form of basal cell carcinoma. RESULTS - Bcl-2 expression was significant in basal cell carcinomas said to be aggressive (morpheaform and nodular types). Of the studied tumors, 66.7% (n =10) strongly expressed p53.Our results show a greater expression of Ki-67 in nodular and superficial basal cell carcinoma, with no expression in the controls. PCNA showed a strong expression in all types of tumors and in the controls. CONCLUSION - The findings allow us to conclude that Bcl-2 and p53 show a tendency to indicate the severity of basal cell carcinoma. In contrast, Ki-67, due to its variable behavior, cannot be considered a marker of severity. Also, PCNA was not a good marker of cell proliferation.

Expressions of p53, cyclinD1 and histopathological features in basal cell carcinomas

BACKGROUND

We planned this study to analyze probable associations between p53, cyclinD1, Ki67 and histopathological features in basal cell carcinomas (BCC).

METHODS

Histological differentiation types, histological growth patterns and tissue responses were analyzed in 50 cases of BCC. In immunohistochemical analysis, p53, cyclinD1 and Ki67 antibodies were investigated. P53 expression was evaluated based on a cut-off value of 25% positivity. CyclinD1 expression was graded from 0 to 3+ according to the percentage of positive nuclear staining. The percentage of positively staining cells for Ki67 was recorded.

RESULTS

The following significant correlations were detected. Solid infiltrative type differentiation was related to the infiltrative histological growth pattern. The rates of p53 positivity and severe fibrosis in the groups of mixed and infiltrative growth patterns were higher than others. Besides, p53-positive cases showed more severe fibrosis and had a higher mean value for Ki67 index. Epidermal p53 and cyclinD1 clones in normal epidermal areas adjacent to tumors were noticed in 42% and 52% of the cases, respectively.

CONCLUSIONS

P53 expression seems to be related to Ki67 index and some histopathological features of BCC, such as infiltrative histological growth pattern and probably fibrosis.

Expression of p53 and p16 in actinic keratosis, bowenoid actinic keratosis and Bowen's disease

INTRODUCTION

Bowen's disease (BD) and bowenoid actinic keratosis (bAK) have traditionally been differentiated according to the presence or absence of dysplasia in the follicular epithelium. p16 has been suggested to be a useful tool to make the differential diagnosis between BD and AK and as a marker of bad prognosis.

MATERIALS

Five biopsies of BD, five of AK and five of bAK where stained for p53 and p16.

RESULTS

All lesions showed positive immunostaining of p53, affecting to the lower two thirds of the epidermis in BD and bAK, and only the basal layer in non-bAK. All the BD and bAK cases were positive for p16, showing a similar immunostaining pattern, whereas no staining was observed in non-bAK.

DISCUSSION AND CONCLUSION

These findings suggest a common pathogenic mechanism for BD and bAK. bAK might have worse prognosis than AK. p16 might not be useful as a tool for differential diagnosis between AK and BD because bAK and BD show an extremely similar immunohistochemical pattern.

Topical thymidine dinucleotide treatment reduces development of ultraviolet-induced basal cell carcinoma in Ptch-1+/- mice

Treatment with thymidine dinucleotide (pTT) has well documented DNA-protective effects and reduces development of squamous cell carcinoma in UV-irradiated mice. The preventive effect of pTT on basal cell carcinoma (BCC) was evaluated in UV-irradiated Ptch-1(+/-) mice, a model of the human disease Gorlin syndrome. Topical pTT treatment significantly reduced the number and size (P < 0.001) of BCCs in murine skin after 7 months of chronic irradiation. Skin biopsies collected 24 hours after the final UV exposure showed that pTT reduced the number of nuclei positive for cyclobutane pyrimidine dimers by 40% (P < 0.0002) and for 8-hydroxy-2'-deoxyguanosine by 61% (P < 0.01 compared with vehicle control). Immunostaining with an antibody specific for mutated p53 revealed 63% fewer positive patches in BCCs of pTT-treated mice compared with controls (P < 0.01), and the number of Ki-67-positive cells was decreased by 56% (P < 0.01) in pTT-treated tumor-free epidermis and by 76% (P < 0.001) in BCC tumor nests (P < 0.001). Terminal dUTP nick-end labeling staining revealed a 213% increase (P < 0.04) in the number of apoptotic cells in BCCs of pTT-treated mice. Cox-2 immunostaining was decreased by 80% in tumor-free epidermis of pTT-treated mice compared with controls (P < 0.01). We conclude that topical pTT treatment during a prolonged period of intermittent UV exposure decreases the number and size of UV-induced BCCs through several anti-cancer mechanisms.

Gene silencing of transcription factor Gli2 inhibits basal cell carcinomalike tumor growth in vivo

Basal cell carcinoma (BCC) belongs worldwide to the most frequent malignancy among Caucasians. The understanding of the molecular mechanisms of BCC formation, which is a prerequisite for the development of efficient new therapies, is still incomplete. The formation of sporadic BCCs in the skin is associated with uncontrolled hedgehog signaling, and the transcription factor Gli2 has been identified as a key mediator or effector of this signaling. There is indication in the literature that preventing Gli2 function may inhibit BCC formation and growth in vivo; however, the mechanism is unclear and difficult to study in humans. Therefore, we used a mouse tumor allograft model to investigate the role of Gli2 in tumor formation. A constitutively Gli2 expressing mouse tumor cell line was stably transfected with Gli2-specific shRNA to induce Gli2 gene silencing or with control shRNA. Injecting the Gli2 gene silenced cells into nude mice for tumor formation we detected a strongly retarded tumor growth compared with control tumor cells. Investigating the mechanisms, we found that Gli2 gene silencing has led to the disruption of the tumor structure as demonstrated by staining tumor sections with hematoxylin. Two main reasons for the tumor destruction were identified. We found that apoptosis was markedly increased while vascularization was strongly decreased in these tumors. Thus, important functions of the transcription factor Gli2 in this tumor model are the prevention of apoptosis and the promotion of microvascularization.

The clinical importance of Ki-67, p16, p14, and p57 expression in patients with advanced ovarian carcinoma

The present study addressed the impact of p14, p16, p57, and Ki-67 in a large cohort of uniformly treated patients with stage III ovarian cancer in relation to other clinicopathologic variables and prognosis. We immunohistochemically studied 171 primary tumors from previously untreated patients with advanced ovarian carcinomas for expression of Ki-67, p16, p14, and p57. High protein levels of Ki-67 (>10% positive nuclei) were found in 144 cases (84%), p16 (>50% positive nuclei) in 53 cases (31%), p57 (>10% positive nuclei) in 41 cases (24%), and p14 (any positive nuclei) in 19 cases (11%). A correlation between high Ki-67 expression and presence of residual disease after primary surgery (P = 0.019), ascites (P = 0.006), higher International Federation of Gynecology and Obstetrics substage (P < 0.001), poor differentiation (P < 0.001), and higher Silverberg histopathologic grade (P < 0.0001) was seen. High expression of p16 correlated to poor differentiation (P = 0.033) and higher Silverberg histopathologic grade (P = 0.018). In univariate analysis, high expression of Ki-67 (P = 0.0001) and p16 (P = 0.005) was associated with poor survival. However, in multivariate analysis, only high expression of Ki-67 was significantly associated with shorter survival (P = 0.025). No correlations were seen between expression of p14 and p57 and clinicopathologic parameters. None of the factors studied was able to predict response to chemotherapy. Our results showed that Ki-67 represents an independent prognostic predictor in stage III ovarian cancer. We did not find p16, p14, and p57 to be useful as prognostic markers.

Expression of cell cycle and apoptosis regulatory proteins in keratoacanthoma and squamous cell carcinoma

Some authors view keratoacanthoma (KA) as a variant of squamous cell carcinoma (SCC), while others consider it a separate entity that must be distinguished from SCC. Involution displayed by KA is an important difference between these two entities. It has been suggested that apoptosis plays a role in the involution process of KA, although the exact trigger for it remains unclear. A hundred and fifty specimens were included in this study, 30 cases for each of the following groups: normal skin (NS), proliferative keratoacanthoma (pKA), regressing keratoacanthoma (rKA), well-differentiated squamous cell carcinoma (wdSCC), and poorly differentiated squamous cell carcinoma (pdSCC). They were immunohistochemically examined for the expression of p53, Ki-67, bak, and bcl-2. Significantly higher p53 and Ki-67 expressions were observed in all tumor lesions examined as compared with NS. There was higher bak expression in KAs compared to NS and a significant reduction of bak expression in pdSCC together with a significant reduction of bak expression in SCCs compared to pKA. Bcl-2 expression was similar in NS and SCCs, but was lower in rKA. We found a significant positive correlation between p53 and Ki-67, p53 and Bak in NS and examined skin tumors. Lower bcl-2 expression in conjunction with higher bak expression in rKA suggests a possible role of these apoptosis-regulating proteins in tumor regression. In contrast to this finding, a steady level of bcl-2 expression in pdSCC combined with lower bak expression levels and a high proliferation rate could contribute to progression and aggressiveness in these tumors. Bak and p53 expression is a sun-related and age-dependent process in NS and skin tumors.

Expression of p53 tumor suppressor protein in sun-exposed skin and associations with sunscreen use and time spent outdoors: a community-based study

The p53 gene is a tumor suppressor gene that is commonly mutated in skin cancer and sun-exposed skin, and this can be detected through immunohistochemical expression of the p53 protein. The authors hypothesized that time spent outdoors is associated with p53 protein expression in human skin and that sunscreen use counteracts the association. In 1996, they investigated this in a community-based cross-sectional study in Australia. Detailed information about skin type, time spent outdoors, and sunscreen use was collected from 139 residents of a subtropical township who also provided a skin biopsy from the back of the hand for measurement of p53 expression. Increasing time spent outdoors was positively associated with immunoreactivity in the whole epidermis and in the basal layer of the epidermis. After adjustment for confounders, p53 immunoreactivity was twice as high for people who used sunscreen 1 or 2 days per week as for those who used sunscreen daily (whole epidermis: ratio estimate=2.0, 95% confidence interval: 1.1, 3.6; basal layer: ratio estimate=1.7, 95% confidence interval: 0.9, 3.1). The authors conclude that p53 immunoreactivity in the skin is a marker of exposure to ultraviolet light in the past 6 months, but this may be mitigated by regular application of sunscreen.