Follicle-stimulating hormone receptor (FSHR) alternative skipping of exon 2 or 3 affects ovarian response to FSH.

Genes critical for fertility are highly conserved in mammals. Interspecies DNA sequence variation, resulting in amino acid substitutions and post-transcriptional modifications, including alternative splicing, are a result of evolution and speciation. The mammalian follicle-stimulating hormone receptor (FSHR) gene encodes distinct species-specific forms by alternative splicing. Skipping of exon 2 of the human FSHR was reported in women of North American origin and correlated with low response to ovarian stimulation with exogenous follicle-stimulating hormone (FSH). To determine whether this variant correlated with low response in women of different genetic backgrounds, we performed a blinded retrospective observational study in a Turkish cohort. Ovarian response was determined as low, intermediate or high according to retrieved oocyte numbers after classifying patients in four age groups (<35, 35-37, 38-40, >40). Cumulus cells collected from 96 women undergoing IVF/ICSI following controlled ovarian hyperstimulation revealed four alternatively spliced FSHR products in seven patients (8%): exon 2 deletion in four patients; exon 3 and exons 2 + 3 deletion in one patient each, and a retention of an intron 1 fragment in one patient. In all others (92%) splicing was intact. Alternative skipping of exons 2, 3 or 2 + 3 were exclusive to low responders and was independent of the use of agonist or antagonist. Interestingly, skipping of exon 3 occurs naturally in the ovaries of domestic cats--a good comparative model for human fertility. We tested the signaling potential of human and cat variants after transfection in HEK293 cells and FSH stimulation. None of the splicing variants initiated cAMP signaling despite high FSH doses, unlike full-length proteins. These data substantiate the occurrence of FSHR exon skipping in a subgroup of low responders and suggest that species-specific regulation of FSHR splicing plays diverse roles in mammalian ovarian function.

Identification and in vitro characterization of follicle stimulating hormone (FSH) receptor variants associated with abnormal ovarian response to FSH.

CONTEXT: FSH mediates cyclic follicle growth and development and is widely used for controlled ovarian stimulation in women undergoing infertility treatment. The ovarian response of women to FSH is variable, ranging from poor response to ovarian hyperstimulation. OBJECTIVE: We investigated whether genetic alterations of the FSH receptor (FSHR) contribute to this variability. DESIGN AND PATIENTS: Our approach was to study women undergoing treatment with in vitro fertilization falling into the edges of the normal distribution of ovarian response to FSH, with respect to age. SETTING: We conducted the study at the Yale Fertility Clinic. METHODS: We extracted RNA from cumulus cells surrounding the oocytes of women undergoing in vitro fertilization and analyzed the FSHR mRNA by RT-PCR and sequencing. RESULTS: We identified four abnormal FSHR splicing products (three exon deletions and one intron insertion) in the FSHR mRNA in 37% (13 of 35) of women tested. All alterations affected the extracellular ligand-binding portion of the receptor without causing a frameshift. When transfected in HEK293T cells, all four splicing variants showed markedly decreased cAMP activation compared to controls. Untransfected cells showed no response to FSH, whereas all the cell lines showed normal cAMP activation when treated with forskolin, a nonreceptor-mediated cAMP stimulant. None of the normal or mutant forms showed any response to LH or TSH. CONCLUSIONS: Our findings strongly indicate FSHR variants as being an intrinsic genetic cause of some forms of infertility and identify a need for functional characterization of these variants and the investigation of more individualized ovarian stimulation protocols.

Active and passive smoking, high-risk human papillomaviruses and cervical neoplasia.

Few studies have evaluated the role of passive smoke exposure and cervical neoplasia risk. We assessed the role of active and passive cigarette smoke exposure and risk of cervical squamous intraepithelial lesion (SIL) in a case-control study based in a South Carolina Health Department; 59 high-grade SIL (HSIL) cases, 313 low-grade SIL (LSIL) cases and 427 controls were recruited and interviewed. Passive cigarette smoke exposure was significantly (P < 0.05) associated with high grade SIL (adjusted odds ratio (aOR) = 2.2) and low-grade SIL (aOR = 1.4). Active smoking was associated with SIL only among White women (aOR = 1.8). High-risk human papillomaviruses (HR-HPVs) appear to interact with active cigarette smoking to increase HSIL risk. HSIL cases compared with LSIL cases were significantly more likely to be HR-HPV positive current smokers (aOR = 3.0; 95% CI: (1.2, 7.7)). These data suggest that active and perhaps passive smoke exposure may be important co-factors in HSIL development among HR-HPV positive women.

CA125 and UQCRFS1 FISH studies of ovarian carcinoma.

OBJECTIVE: With the gene CA125 having recently been cloned, we chose to investigate the gene copy number of various ovarian cancer samples by FISH. As a control we chose BACs close to the chromosome 19 centromere. One of these BACs carries the gene UQCRFS1. METHODS: We developed FISH probes for CA125 and the UQCRFS1 region. We studied 22 touch preparations and 14 paraffin-embedded samples of ovarian carcinomas with known CA125 serum levels, two ovarian cancer cell lines, and one ascites sample from an ovarian cancer patient. The average copy number per cell of both probes was calculated. Metaphase analyses were done on cell lines and ascites cells to localize the signals. RESULTS: The CA125 gene mapped to 19p13.2. Three of 22 (13.6%) touch preparations and 1 of 14 (7.1%) paraffin samples had amplified levels of CA125. The cell lines and ascites sample did not have amplified CA125. Unexpectedly, 3 of 22 (13.6%) touch preparations, 1 of 14 (7.1%) paraffin samples, one cell line, and the ascites sample had amplification of the UQCRFS1 region. The amplification of the UQCRFS1 region occurred in the form of homogeneously staining regions (HSRs). Only one sample had coamplification of CA125 and UQCRFS1. CONCLUSIONS: CA125 was only sometimes modestly amplified in ovarian carcinoma, even when the serum CA125 level was highly elevated. Unexpectedly, the UQCRFS1 region was also sometimes amplified as HSRs. The UQCRFS1 protein is also known as complex III of the mitochondrial respiratory chain. This product may have an important role in malignant cells.

The use of FISH on breast core needle samples for the presurgical assessment of HER-2 oncogene status.

HER-2 status has been used in breast carcinoma as a prognostic marker to predict drug response and to select patients for trastuzumab treatment. Since immunohistochemistry (IHC) is thought to be less reliable, HER-2 testing with FISH is preferred. The analysis of HER-2 is usually performed on formalin-fixed paraffin tissue sections obtained from surgery. The use of paraffin sections is very time consuming and labor intensive. The objectives of this study were to (1) develop a simple and quick FISH protocol using touch imprints of breast core needle biopsies, eliminating the deparaffinization and pretreatment; and (2) make the HER-2 status available at the presurgical multidisciplinary treatment planning conference. A total of 50 core samples of breast carcinoma were obtained from image-guided core needle biopsy. Both FISH and IHC data were available for 46 cases. Forty-four of 46 cases (95.7%) were consistent. Two IHC 2+ cases were nonamplified (ratios of 0.99 and 1.09). It is expected that, in the near future, additional molecular markers will be used before surgery when the overall treatment plan is being developed. We conclude that HER-2 gene analysis by FISH on breast touch imprints is easily done and is a useful and reliable technique.